Hyperledger Fabric sample Using Event Handling with IBM Blockchain Platform V2.0

# Liberty House Club **A Parallel Binance Chain to Enable Smart Contracts** _NOTE: This document is under development. Please check regularly for updates!_ ## Table of Contents - [Motivation](#motivation) - [Design Principles](#design-principles) - [Consensus and Validator Quorum](#consensus-and-validator-quorum) * [Proof of Staked Authority](#proof-of-staked-authority) * [Validator Quorum](#validator-quorum) * [Security and Finality](#security-and-finality) * [Reward](#reward) - [Token Economy](#token-economy) * [Native Token](#native-token) * [Other Tokens](#other-tokens) - [Cross-Chain Transfer and Communication](#cross-chain-transfer-and-communication) * [Cross-Chain Transfer](#cross-chain-transfer) * [BC to BSC Architecture](#bc-to-bsc-architecture) * [BSC to BC Architecture](#bsc-to-bc-architecture) * [Timeout and Error Handling](#timeout-and-error-handling) * [Cross-Chain User Experience](#cross-chain-user-experience) * [Cross-Chain Contract Event](#cross-chain-contract-event) - [Staking and Governance](#staking-and-governance) * [Staking on BC](#staking-on-bc) * [Rewarding](#rewarding) * [Slashing](#slashing) - [Relayers](#relayers) * [BSC Relayers](#bsc-relayers) * [Oracle Relayers](#oracle-relayers) - [Outlook](#outlook) # Motivation After its mainnet community [launch](https://www.binance.com/en/blog/327334696200323072/Binance-DEX-Launches-on-Binance-Chain-Invites-Further-Community-Development) in April 2019, [Binance Chain](https://www.binance.org) has exhibited its high speed and large throughput design. Binance Chain’s primary focus, its native [decentralized application](https://en.wikipedia.org/wiki/Decentralized_application) (“dApp”) [Binance DEX](https://www.binance.org/trade), has demonstrated its low-latency matching with large capacity headroom by handling millions of trading volume in a short time. Flexibility and usability are often in an inverse relationship with performance. The concentration on providing a convenient digital asset issuing and trading venue also brings limitations. Binance Chain's most requested feature is the programmable extendibility, or simply the [Smart Contract](https://en.wikipedia.org/wiki/Smart_contract) and Virtual Machine functions. Digital asset issuers and owners struggle to add new decentralized features for their assets or introduce any sort of community governance and activities. Despite this high demand for adding the Smart Contract feature onto Binance Chain, it is a hard decision to make. The execution of a Smart Contract may slow down the exchange function and add non-deterministic factors to trading. If that compromise could be tolerated, it might be a straightforward idea to introduce a new Virtual Machine specification based on [Tendermint](https://tendermint.com/core/), based on the current underlying consensus protocol and major [RPC](https://docs.binance.org/api-reference/node-rpc.html) implementation of Binance Chain. But all these will increase the learning requirements for all existing dApp communities, and will not be very welcomed. We propose a parallel blockchain of the current Binance Chain to retain the high performance of the native DEX blockchain and to support a friendly Smart Contract function at the same time. # Design Principles After the creation of the parallel blockchain into the Binance Chain ecosystem, two blockchains will run side by side to provide different services. The new parallel chain will be called “**Binance Smart Chain**” (short as “**BSC**” for the below sections), while the existing mainnet remains named “**Binance Chain**” (short as “**BC**” for the below sections). Here are the design principles of **BSC**: 1. **Standalone Blockchain**: technically, BSC is a standalone blockchain, instead of a layer-2 solution. Most BSC fundamental technical and business functions should be self-contained so that it can run well even if the BC stopped for a short period. 2. **Ethereum Compatibility**: The first practical and widely-used Smart Contract platform is Ethereum. To take advantage of the relatively mature applications and community, BSC chooses to be compatible with the existing Ethereum mainnet. This means most of the **dApps**, ecosystem components, and toolings will work with BSC and require zero or minimum changes; BSC node will require similar (or a bit higher) hardware specification and skills to run and operate. The implementation should leave room for BSC to catch up with further Ethereum upgrades. 3. **Staking Involved Consensus and Governance**: Staking-based consensus is more environmentally friendly and leaves more flexible option to the community governance. Expectedly, this consensus should enable better network performance over [proof-of-work](https://en.wikipedia.org/wiki/Proof_of_work) blockchain system, i.e., faster blocking time and higher transaction capacity. 4. **Native Cross-Chain Communication**: both BC and BSC will be implemented with native support for cross-chain communication among the two blockchains. The communication protocol should be bi-directional, decentralized, and trustless. It will concentrate on moving digital assets between BC and BSC, i.e., [BEP2](https://github.com/binance-chain/BEPs/blob/master/BEP2.md) tokens, and eventually, other BEP tokens introduced later. The protocol should care for the minimum of other items stored in the state of the blockchains, with only a few exceptions. # Consensus and Validator Quorum Based on the above design principles, the consensus protocol of BSC is to fulfill the following goals: 1. Blocking time should be shorter than Ethereum network, e.g. 5 seconds or even shorter. 2. It requires limited time to confirm the finality of transactions, e.g. around 1-min level or shorter. 3. There is no inflation of native token: BNB, the block reward is collected from transaction fees, and it will be paid in BNB. 4. It is compatible with Ethereum system as much as possible. 5. It allows modern [proof-of-stake](https://en.wikipedia.org/wiki/Proof_of_stake) blockchain network governance. ## Proof of Staked Authority Although Proof-of-Work (PoW) has been recognized as a practical mechanism to implement a decentralized network, it is not friendly to the environment and also requires a large size of participants to maintain the security. Ethereum and some other blockchain networks, such as [MATIC Bor](https://github.com/maticnetwork/bor), [TOMOChain](https://tomochain.com/), [GoChain](https://gochain.io/), [xDAI](https://xdai.io/), do use [Proof-of-Authority(PoA)](https://en.wikipedia.org/wiki/Proof_of_authority) or its variants in different scenarios, including both testnet and mainnet. PoA provides some defense to 51% attack, with improved efficiency and tolerance to certain levels of Byzantine players (malicious or hacked). It serves as an easy choice to pick as the fundamentals. Meanwhile, the PoA protocol is most criticized for being not as decentralized as PoW, as the validators, i.e. the nodes that take turns to produce blocks, have all the authorities and are prone to corruption and security attacks. Other blockchains, such as EOS and Lisk both, introduce different types of [Delegated Proof of Stake (DPoS)](https://en.bitcoinwiki.org/wiki/DPoS) to allow the token holders to vote and elect the validator set. It increases the decentralization and favors community governance. BSC here proposes to combine DPoS and PoA for consensus, so that: 1. Blocks are produced by a limited set of validators 2. Validators take turns to produce blocks in a PoA manner, similar to [Ethereum’s Clique](https://eips.ethereum.org/EIPS/eip-225) consensus design 3. Validator set are elected in and out based on a staking based governance ## Validator Quorum In the genesis stage, a few trusted nodes will run as the initial Validator Set. After the blocking starts, anyone can compete to join as candidates to elect as a validator. The staking status decides the top 21 most staked nodes to be the next validator set, and such an election will repeat every 24 hours. **BNB** is the token used to stake for BSC. In order to remain as compatible as Ethereum and upgradeable to future consensus protocols to be developed, BSC chooses to rely on the **BC** for staking management (Please refer to the below “[Staking and Governance](#staking-and-governance)” section). There is a **dedicated staking module for BSC on BC**. It will accept BSC staking from BNB holders and calculate the highest staked node set. Upon every UTC midnight, BC will issue a verifiable `ValidatorSetUpdate` cross-chain message to notify BSC to update its validator set. While producing further blocks, the existing BSC validators check whether there is a `ValidatorSetUpdate` message relayed onto BSC periodically. If there is, they will update the validator set after an **epoch period**, i.e. a predefined number of blocking time. For example, if BSC produces a block every 5 seconds, and the epoch period is 240 blocks, then the current validator set will check and update the validator set for the next epoch in 1200 seconds (20 minutes). ## Security and Finality Given there are more than ½\*N+1 validators are honest, PoA based networks usually work securely and properly. However, there are still cases where certain amount Byzantine validators may still manage to attack the network, e.g. through the “[Clone Attack](https://arxiv.org/pdf/1902.10244.pdf)”. To secure as much as BC, BSC users are encouraged to wait until receiving blocks sealed by more than ⅔\*N+1 different validators. In that way, the BSC can be trusted at a similar security level to BC and can tolerate less than ⅓\*N Byzantine validators. With 21 validators, if the block time is 5 seconds, the ⅔\*N+1 different validator seals will need a time period of (⅔\*21+1)*5 = 75 seconds. Any critical applications for BSC may have to wait for ⅔\*N+1 to ensure a relatively secure finality. However, besides such arrangement, BSC does introduce **Slashing** logic to penalize Byzantine validators for **double signing** or **inavailability**, which will be covered in the “Staking and Governance” section later. This Slashing logic will expose the malicious validators in a very short time and make the “Clone Attack” very hard or extremely non-beneficial to execute. With this enhancement, ½\*N+1 or even fewer blocks are enough as confirmation for most transactions. ## Reward All the BSC validators in the current validator set will be rewarded with transaction **fees in BNB**. As BNB is not an inflationary token, there will be no mining rewards as what Bitcoin and Ethereum network generate, and the gas fee is the major reward for validators. As BNB is also utility tokens with other use cases, delegators and validators will still enjoy other benefits of holding BNB. The reward for validators is the fees collected from transactions in each block. Validators can decide how much to give back to the delegators who stake their BNB to them, in order to attract more staking. Every validator will take turns to produce the blocks in the same probability (if they stick to 100% liveness), thus, in the long run, all the stable validators may get a similar size of the reward. Meanwhile, the stakes on each validator may be different, so this brings a counter-intuitive situation that more users trust and delegate to one validator, they potentially get less reward. So rational delegators will tend to delegate to the one with fewer stakes as long as the validator is still trustful (insecure validator may bring slashable risk). In the end, the stakes on all the validators will have less variation. This will actually prevent the stake concentration and “winner wins forever” problem seen on some other networks. Some parts of the gas fee will also be rewarded to relayers for Cross-Chain communication. Please refer to the “[Relayers](#relayers)” section below. # Token Economy BC and BSC share the same token universe for BNB and BEP2 tokens. This defines: 1. The same token can circulate on both networks, and flow between them bi-directionally via a cross-chain communication mechanism. 2. The total circulation of the same token should be managed across the two networks, i.e. the total effective supply of a token should be the sum of the token’s total effective supply on both BSC and BC. 3. The tokens can be initially created on BSC in a similar format as ERC20 token standard, or on BC as a BEP2, then created on the other. There are native ways on both networks to link the two and secure the total supply of the token. ## Native Token BNB will run on BSC in the same way as ETH runs on Ethereum so that it remains as “native token” for both BSC and BC. This means, in addition to BNB is used to pay most of the fees on Binance Chain and Binance DEX, BNB will be also used to: 1. pay “fees“ to deploy smart contracts on BSC 2. stake on selected BSC validators, and get corresponding rewards 3. perform cross-chain operations, such as transfer token assets across BC and BSC ### Seed Fund Certain amounts of BNB will be burnt on BC and minted on BSC during its genesis stage. This amount is called “Seed Fund” to circulate on BSC after the first block, which will be dispatched to the initial BC-to-BSC Relayer(described in later sections) and initial validator set introduced at genesis. These BNBs are used to pay transaction fees in the early stage to transfer more BNB from BC onto BSC via the cross-chain mechanism. The BNB cross-chain transfer is discussed in a later section, but for BC to BSC transfer, it is generally to lock BNB on BC from the source address of the transfer to a system-controlled address and unlock the corresponding amount from special contract to the target address of the transfer on BSC, or reversely, when transferring from BSC to BC, it is to lock BNB from the source address on BSC into a special contract and release locked amount on BC from the system address to the target address. The logic is related to native code on BC and a series of smart contracts on BSC. ## Other Tokens BC supports BEP2 tokens and upcoming [BEP8 tokens](https://github.com/binance-chain/BEPs/pull/69), which are native assets transferrable and tradable (if listed) via fast transactions and sub-second finality. Meanwhile, as BSC is Ethereum compatible, it is natural to support ERC20 tokens on BSC, which here is called “**BEP2E**” (with the real name to be introduced by the future BEPs,it potentially covers BEP8 as well). BEP2E may be “Enhanced” by adding a few more methods to expose more information, such as token denomination, decimal precision definition and the owner address who can decide the Token Binding across the chains. BSC and BC work together to ensure that one token can circulate in both formats with confirmed total supply and be used in different use cases. ### Token Binding BEP2 tokens will be extended to host a new attribute to associate the token with a BSC BEP2E token contract, called “**Binder**”, and this process of association is called “**Token Binding**”. Token Binding can happen at any time after BEP2 and BEP2E are ready. The token owners of either BEP2 or BEP2E don’t need to bother about the Binding, until before they really want to use the tokens on different scenarios. Issuers can either create BEP2 first or BEP2E first, and they can be bound at a later time. Of course, it is encouraged for all the issuers of BEP2 and BEP2E to set the Binding up early after the issuance. A typical procedure to bind the BEP2 and BEP2E will be like the below: 1. Ensure both the BEP2 token and the BEP2E token both exist on each blockchain, with the same total supply. BEP2E should have 3 more methods than typical ERC20 token standard: * symbol(): get token symbol * decimals(): get the number of the token decimal digits * owner(): get **BEP2E contract owner’s address.** This value should be initialized in the BEP2E contract constructor so that the further binding action can verify whether the action is from the BEP2E owner. 2. Decide the initial circulation on both blockchains. Suppose the total supply is *S*, and the expected initial circulating supply on BC is *K*, then the owner should lock S-K tokens to a system controlled address on BC. 3. Equivalently, *K* tokens is locked in the special contract on BSC, which handles major binding functions and is named as **TokenHub**. The issuer of the BEP2E token should lock the *K* amount of that token into TokenHub, resulting in *S-K* tokens to circulate on BSC. Thus the total circulation across 2 blockchains remains as *S*. 4. The issuer of BEP2 token sends the bind transaction on BC. Once the transaction is executed successfully after proper verification: * It transfers *S-K* tokens to a system-controlled address on BC. * A cross-chain bind request package will be created, waiting for Relayers to relay. 5. BSC Relayers will relay the cross-chain bind request package into **TokenHub** on BSC, and the corresponding request and information will be stored into the contract. 6. The contract owner and only the owner can run a special method of TokenHub contract, `ApproveBind`, to verify the binding request to mark it as a success. It will confirm: * the token has not been bound; * the binding is for the proper symbol, with proper total supply and decimal information; * the proper lock are done on both networks; 10. Once the `ApproveBind` method has succeeded, TokenHub will mark the two tokens are bounded and share the same circulation on BSC, and the status will be propagated back to BC. After this final confirmation, the BEP2E contract address and decimals will be written onto the BEP2 token as a new attribute on BC, and the tokens can be transferred across the two blockchains bidirectionally. If the ApproveBind fails, the failure event will also be propagated back to BC to release the locked tokens, and the above steps can be re-tried later. # Cross-Chain Transfer and Communication Cross-chain communication is the key foundation to allow the community to take advantage of the dual chain structure: * users are free to create any tokenization, financial products, and digital assets on BSC or BC as they wish * the items on BSC can be manually and programmingly traded and circulated in a stable, high throughput, lighting fast and friendly environment of BC * users can operate these in one UI and tooling ecosystem. ## Cross-Chain Transfer The cross-chain transfer is the key communication between the two blockchains. Essentially the logic is: 1. the `transfer-out` blockchain will lock the amount from source owner addresses into a system controlled address/contracts; 2. the `transfer-in` blockchain will unlock the amount from the system controlled address/contracts and send it to target addresses. The cross-chain transfer package message should allow the BSC Relayers and BC **Oracle Relayers** to verify: 1. Enough amount of token assets are removed from the source address and locked into a system controlled addresses/contracts on the source blockchain. And this can be confirmed on the target blockchain. 2. Proper amounts of token assets are released from a system controlled addresses/contracts and allocated into target addresses on the target blockchain. If this fails, it can be confirmed on source blockchain, so that the locked token can be released back (may deduct fees). 3. The sum of the total circulation of the token assets across the 2 blockchains are not changed after this transfer action completes, no matter if the transfer succeeds or not.  The architecture of cross-chain communication is as in the above diagram. To accommodate the 2 heteroid systems, communication handling is different in each direction. ## BC to BSC Architecture BC is a Tendermint-based, instant finality blockchain. Validators with at least ⅔\*N+1 of the total voting power will co-sign each block on the chain. So that it is practical to verify the block transactions and even the state value via **Block Header** and **Merkle Proof** verification. This has been researched and implemented as “**Light-Client Protocol**”, which are intensively discussed in [the Ethereum](https://github.com/ethereum/wiki/wiki/Light-client-protocol) community, studied and implemented for [Cosmos inter-chain communication](https://github.com/cosmos/ics/blob/a4173c91560567bdb7cc9abee8e61256fc3725e9/spec/ics-007-tendermint-client/README.md). BC-to-BSC communication will be verified in an “**on-chain light client**” implemented via BSC **Smart Contracts** (some of them may be **“pre-compiled”**). After some transactions and state change happen on BC, if a transaction is defined to trigger cross-chain communication,the Cross-chain “**package**” message will be created and **BSC Relayers** will pass and submit them onto BSC as data into the "build-in system contracts". The build-in system contracts will verify the package and execute the transactions if it passes the verification. The verification will be guaranteed with the below design: 1. BC blocking status will be synced to the light client contracts on BSC from time to time, via block header and pre-commits, for the below information: * block and app hash of BC that are signed by validators * current validatorset, and validator set update 2. the key-value from the blockchain state will be verified based on the Merkle Proof and information from above #1. After confirming the key-value is accurate and trustful, the build-in system contracts will execute the actions corresponding to the cross-chain packages. Some examples of such packages that can be created for BC-to-BSC are: 1. Bind: bind the BEP2 tokens and BEP2E 2. Transfer: transfer tokens after binding, this means the circulation will decrease (be locked) from BC and appear in the target address balance on BSC 3. Error Handling: to handle any timeout/failure event for BSC-to-BC communication 4. Validatorset update of BSC To ensure no duplication, proper message sequence and timely timeout, there is a “Channel” concept introduced on BC to manage any types of the communication. For relayers, please also refer to the below “Relayers” section. ## BSC to BC Architecture BSC uses Proof of Staked Authority consensus protocol, which has a chance to fork and requires confirmation of more blocks. One block only has the signature of one validator, so that it is not easy to rely on one block to verify data from BSC. To take full advantage of validator quorum of BC, an idea similar to many [Bridge ](https://github.com/poanetwork/poa-bridge)or Oracle blockchains is adopted: 1. The cross-chain communication requests from BSC will be submitted and executed onto BSC as transactions. The execution of the transanction wil emit `Events`, and such events can be observed and packaged in certain “**Oracle**” onto BC. Instead of Block Headers, Hash and Merkle Proof, this type of “Oracle” package directly contains the cross-chain information for actions, such as sender, receiver and amount for transfer. 2. To ensure the security of the Oracle, the validators of BC will form anothe quorum of “**Oracle Relayers**”. Each validator of the BC should run a **dedicated process** as the Oracle Relayer. These Oracle Relayers will submit and vote for the cross-chain communication package, like Oracle, onto BC, using the same validator keys. Any package signed by more than ⅔\*N+1 Oracle Relayers’ voting power is as secure as any block signed by ⅔\*N+1 of the same quorum of validators’ voting power. By using the same validator quorum, it saves the light client code on BC and continuous block updates onto BC. Such Oracles also have Oracle IDs and types, to ensure sequencing and proper error handling. ## Timeout and Error Handling There are scenarios that the cross-chain communication fails. For example, the relayed package cannot be executed on BSC due to some coding bug in the contracts. **Timeout and error handling logics are** used in such scenarios. For the recognizable user and system errors or any expected exceptions, the two networks should heal themselves. For example, when BC to BSC transfer fails, BSC will issue a failure event and Oracle Relayers will execute a refund on BC; when BSC to BC transfer fails, BC will issue a refund package for Relayer to relay in order to unlock the fund. However, unexpected error or exception may still happen on any step of the cross-chain communication. In such a case, the Relayers and Oracle Relayers will discover that the corresponding cross-chain channel is stuck in a particular sequence. After a Timeout period, the Relayers and Oracle Relayers can request a “SkipSequence” transaction, the stuck sequence will be marked as “Unexecutable”. A corresponding alerts will be raised, and the community has to discuss how to handle this scenario, e.g. payback via the sponsor of the validators, or event clear the fund during next network upgrade. ## Cross-Chain User Experience Ideally, users expect to use two parallel chains in the same way as they use one single chain. It requires more aggregated transaction types to be added onto the cross-chain communication to enable this, which will add great complexity, tight coupling, and maintenance burden. Here BC and BSC only implement the basic operations to enable the value flow in the initial launch and leave most of the user experience work to client side UI, such as wallets. E.g. a great wallet may allow users to sell a token directly from BSC onto BC’s DEX order book, in a secure way. ## Cross-Chain Contract Event Cross-Chain Contract Event (CCCE) is designed to allow a smart contract to trigger cross-chain transactions, directly through the contract code. This becomes possible based on: 1. Standard system contracts can be provided to serve operations callable by general smart contracts; 2. Standard events can be emitted by the standard contracts; 3. Oracle Relayers can capture the standard events, and trigger the corresponding cross-chain operations; 4. Dedicated, code-managed address (account) can be created on BC and accessed by the contracts on the BSC, here it is named as **“Contract Address on BC” (CAoB)**. Several standard operations are implemented: 1. BSC to BC transfer: this is implemented in the same way as normal BSC to BC transfer, by only triggered via standard contract. The fund can be transferred to any addresses on BC, including the corresponding CAoB of the transfer originating contract. 2. Transfer on BC: this is implemented as a special cross-chain transfer, while the real transfer is from **CAoB** to any other address (even another CAoB). 3. BC to BSC transfer: this is implemented as two-pass cross-chain communication. The first is triggered by the BSC contract and propagated onto BC, and then in the second pass, BC will start a normal BC to BSC cross-chain transfer, from **CAoB** to contract address on BSC. A special note should be paid on that the BSC contract only increases balance upon any transfer coming in on the second pass, and the error handling in the second pass is the same as the normal BC to BSC transfer. 4. IOC (Immediate-Or-Cancel) Trade Out: the primary goal of transferring assets to BC is to trade. This event will instruct to trade a certain amount of an asset in CAoB into another asset as much as possible and transfer out all the results, i.e. the left the source and the traded target tokens of the trade, back to BSC. BC will handle such relayed events by sending an “Immediate-Or-Cancel”, i.e. IOC order onto the trading pairs, once the next matching finishes, the result will be relayed back to BSC, which can be in either one or two assets. 5. Auction Trade Out: Such event will instruct BC to send an auction order to trade a certain amount of an asset in **CAoB** into another asset as much as possible and transfer out all the results back to BSC at the end of the auction. Auction function is upcoming on BC. There are some details for the Trade Out: 1. both can have a limit price (absolute or relative) for the trade; 2. the end result will be written as cross-chain packages to relay back to BSC; 3. cross-chain communication fees may be charged from the asset transferred back to BSC; 4. BSC contract maintains a mirror of the balance and outstanding orders on CAoB. No matter what error happens during the Trade Out, the final status will be propagated back to the originating contract and clear its internal state. With the above features, it simply adds the cross-chain transfer and exchange functions with high liquidity onto all the smart contracts on BSC. It will greatly add the application scenarios on Smart Contract and dApps, and make 1 chain +1 chain > 2 chains. # Staking and Governance Proof of Staked Authority brings in decentralization and community involvement. Its core logic can be summarized as the below. You may see similar ideas from other networks, especially Cosmos and EOS. 1. Token holders, including the validators, can put their tokens “**bonded**” into the stake. Token holders can **delegate** their tokens onto any validator or validator candidate, to expect it can become an actual validator, and later they can choose a different validator or candidate to **re-delegate** their tokens¹. 2. All validator candidates will be ranked by the number of bonded tokens on them, and the top ones will become the real validators. 3. Validators can share (part of) their blocking reward with their delegators. 4. Validators can suffer from “**Slashing**”, a punishment for their bad behaviors, such as double sign and/or instability. 5. There is an “**unbonding period**” for validators and delegators so that the system makes sure the tokens remain bonded when bad behaviors are caught, the responsible will get slashed during this period. ## Staking on BC Ideally, such staking and reward logic should be built into the blockchain, and automatically executed as the blocking happens. Cosmos Hub, who shares the same Tendermint consensus and libraries with Binance Chain, works in this way. BC has been preparing to enable staking logic since the design days. On the other side, as BSC wants to remain compatible with Ethereum as much as possible, it is a great challenge and efforts to implement such logic on it. This is especially true when Ethereum itself may move into a different Proof of Stake consensus protocol in a short (or longer) time. In order to keep the compatibility and reuse the good foundation of BC, the staking logic of BSC is implemented on BC: 1. The staking token is BNB, as it is a native token on both blockchains anyway 2. The staking, i.e. token bond and delegation actions and records for BSC, happens on BC. 3. The BSC validator set is determined by its staking and delegation logic, via a staking module built on BC for BSC, and propagated every day UTC 00:00 from BC to BSC via Cross-Chain communication. 4. The reward distribution happens on BC around every day UTC 00:00. ## Rewarding Both the validator update and reward distribution happen every day around UTC 00:00. This is to save the cost of frequent staking updates and block reward distribution. This cost can be significant, as the blocking reward is collected on BSC and distributed on BC to BSC validators and delegators. (Please note BC blocking fees will remain rewarding to BC validators only.) A deliberate delay is introduced here to make sure the distribution is fair: 1. The blocking reward will not be sent to validator right away, instead, they will be distributed and accumulated on a contract; 2. Upon receiving the validator set update into BSC, it will trigger a few cross-chain transfers to transfer the reward to custody addresses on the corresponding validators. The custody addresses are owned by the system so that the reward cannot be spent until the promised distribution to delegators happens. 3. In order to make the synchronization simpler and allocate time to accommodate slashing, the reward for N day will be only distributed in N+2 days. After the delegators get the reward, the left will be transferred to validators’ own reward addresses. ## Slashing Slashing is part of the on-chain governance, to ensure the malicious or negative behaviors are punished. BSC slash can be submitted by anyone. The transaction submission requires **slash evidence** and cost fees but also brings a larger reward when it is successful. So far there are two slashable cases. ### Double Sign It is quite a serious error and very likely deliberate offense when a validator signs more than one block with the same height and parent block. The reference protocol implementation should already have logic to prevent this, so only the malicious code can trigger this. When Double Sign happens, the validator should be removed from the Validator **Set** right away. Anyone can submit a slash request on BC with the evidence of Double Sign of BSC, which should contain the 2 block headers with the same height and parent block, sealed by the offending validator. Upon receiving the evidence, if the BC verifies it to be valid: 1. The validator will be removed from validator set by an instance BSC validator set update Cross-Chain update; 2. A predefined amount of BNB would be slashed from the **self-delegated** BNB of the validator; Both validator and its delegators will not receive the staking rewards. 3. Part of the slashed BNB will allocate to the submitter’s address, which is a reward and larger than the cost of submitting slash request transaction 4. The rest of the slashed BNB will allocate to the other validators’ custody addresses, and distributed to all delegators in the same way as blocking reward. ### Inavailability The liveness of BSC relies on everyone in the Proof of Staked Authority validator set can produce blocks timely when it is their turn. Validators can miss their turn due to any reason, especially problems in their hardware, software, configuration or network. This instability of the operation will hurt the performance and introduce more indeterministic into the system. There can be an internal smart contract responsible for recording the missed blocking metrics of each validator. Once the metrics are above the predefined threshold, the blocking reward for validator will not be relayed to BC for distribution but shared with other better validators. In such a way, the poorly-operating validator should be gradually voted out of the validator set as their delegators will receive less or none reward. If the metrics remain above another higher level of threshold, the validator will be dropped from the rotation, and this will be propagated back to BC, then a predefined amount of BNB would be slashed from the **self-delegated** BNB of the validator. Both validators and delegators will not receive their staking rewards. ### Governance Parameters There are many system parameters to control the behavior of the BSC, e.g. slash amount, cross-chain transfer fees. All these parameters will be determined by BSC Validator Set together through a proposal-vote process based on their staking. Such the process will be carried on BC, and the new parameter values will be picked up by corresponding system contracts via a cross-chain communication. # Relayers Relayers are responsible to submit Cross-Chain Communication Packages between the two blockchains. Due to the heterogeneous parallel chain structure, two different types of Relayers are created. ## BSC Relayers Relayers for BC to BSC communication referred to as “**BSC Relayers**”, or just simply “Relayers”. Relayer is a standalone process that can be run by anyone, and anywhere, except that Relayers must register themselves onto BSC and deposit a certain refundable amount of BNB. Only relaying requests from the registered Relayers will be accepted by BSC. The package they relay will be verified by the on-chain light client on BSC. The successful relay needs to pass enough verification and costs gas fees on BSC, and thus there should be incentive reward to encourage the community to run Relayers. ### Incentives There are two major communication types: 1. Users triggered Operations, such as `token bind` or `cross chain transfer`. Users must pay additional fee to as relayer reward. The reward will be shared with the relayers who sync the referenced blockchain headers. Besides, the reward won't be paid the relayers' accounts directly. A reward distribution mechanism will be brought in to avoid monopolization. 2. System Synchronization, such as delivering `refund package`(caused by failures of most oracle relayers), special blockchain header synchronization(header contains BC validatorset update), BSC staking package. System reward contract will pay reward to relayers' accounts directly. If some Relayers have faster networks and better hardware, they can monopolize all the package relaying and leave no reward to others. Thus fewer participants will join for relaying, which encourages centralization and harms the efficiency and security of the network. Ideally, due to the decentralization and dynamic re-election of BSC validators, one Relayer can hardly be always the first to relay every message. But in order to avoid the monopolization further, the rewarding economy is also specially designed to minimize such chance: 1. The reward for Relayers will be only distributed in batches, and one batch will cover a number of successful relayed packages. 2. The reward a Relayer can get from a batch distribution is not linearly in proportion to their number of successful relayed packages. Instead, except the first a few relays, the more a Relayer relays during a batch period, the less reward it will collect. ## Oracle Relayers Relayers for BSC to BC communication are using the “Oracle” model, and so-called “**Oracle Relayers**”. Each of the validators must, and only the ones of the validator set, run Oracle Relayers. Each Oracle Relayer watches the blockchain state change. Once it catches Cross-Chain Communication Packages, it will submit to vote for the requests. After Oracle Relayers from ⅔ of the voting power of BC validators vote for the changes, the cross-chain actions will be performed. Oracle Replayers should wait for enough blocks to confirm the finality on BSC before submitting and voting for the cross-chain communication packages onto BC. The cross-chain fees will be distributed to BC validators together with the normal BC blocking rewards. Such oracle type relaying depends on all the validators to support. As all the votes for the cross-chain communication packages are recorded on the blockchain, it is not hard to have a metric system to assess the performance of the Oracle Relayers. The poorest performer may have their rewards clawed back via another Slashing logic introduced in the future. # Outlook It is hard to conclude for Binance Chain, as it has never stopped evolving. The dual-chain strategy is to open the gate for users to take advantage of the fast transferring and trading on one side, and flexible and extendable programming on the other side, but it will be one stop along the development of Binance Chain. Here below are the topics to look into so as to facilitate the community better for more usability and extensibility: 1. Add different digital asset model for different business use cases 2. Enable more data feed, especially DEX market data, to be communicated from Binance DEX to BSC 3. Provide interface and compatibility to integrate with Ethereum, including its further upgrade, and other blockchain 4. Improve client side experience to manage wallets and use blockchain more conveniently ------ [1]: BNB business practitioners may provide other benefits for BNB delegators, as they do now for long term BNB holders.

WARNING: This repository is no longer maintained :warning: This repository, which contains assets to run a Hyperledger Composer application, is not being actively maintained due to a shift to focus on Hyperledger Fabric. This repository will not be updated. Refer to https://github.com/IBM/auction-events for a similar example.

A sample Auction House application in F# with event sourcing by Marten / PostgreSQL.

A website announcing a vehicle auction event. Some sections are dynamically created by JavaScript

Web auction platform implemented with CQRS and event sourcing patterns Built with ASP.NET Core, Angular 8, SQL Server, MongoDB. Containerized and tested.

Date of Concorde In January of the year 1976 after 29 years of the first to penetrate to the speed of sound military aircraft jet - Two Concord took off together at the same time, one from London and one from Paris, the first airline service ultrasound for travelers. The aircraft Almottaghtan has looked towards the west as if they were Tgaraan - even Tsabakan - the sun. Where they arrived as if they did not Taathrca, in terms of time, in a new event launches air transport stage supersonic passenger wealthy people who do not allow them to narrow their time to stay in the air for long periods. How the project began and evolved, and how the outcome of the remaining Concorde lounges to museums ... This is what Santapah in the following lines: The emergence of the Concorde The deal "supersonic" between England and France was signed in 1962, for the design and construction of the first civilian supersonic plane manufactured by Airbus for them. After long years of arduous efforts and research strenuous, in addition to more than 5,000 hours in the air tunnels, proved to be a form of equity Almstrq with the body long cylinder for aircraft relatively large passengers, it is the best form executable command and control speeds ultrasound. The first two aircraft of this type making and Tjeribhma in 1969, and since then about 20 aircraft of this model, called the "Concord" was produced (the only civilian aircraft that exceed the speed of sound speed), and who serve in the British Airways and Air France in income 1976, the rate of seven aircraft of the British lines and five lines in French. The first fly line is the London - Singapore via Bahrain. In 1976 received Bahrain Airport very important event, which is to start regular flights between Bahrain and London, the fastest of the British Airways sound Concorde, the airport first and the only one who was receiving this type of aircraft in the Middle East, given that the Concorde need to Airports women with special specifications, so they need to take-off and landing runways longer than the regular airports runways, and the noise from the power of their engines leads to smash windows of buildings ordinary airports, and the speed has a crush Madarjha. What Concorde is distinct from other aircraft?Characterized by Concorde slim form in the form of a triangle (delta). And fly faster and higher than other aircraft altitudes, using the "upward vortex" method to accomplish extraordinary mission. For example, while the "Boeing 747" aircraft speed, better known as "jumbo" around 900 km / h (about 84.0 Mach) at an altitude of 35 thousand feet, the Concorde fly quickly 2172 km / h (Mach 2) at an altitude of 60 thousand Foot. It is known that Almaj is the real rate of speed compared to the speed of sound, and is equivalent to an average of 1225 kilometers per hour, so that the speed of sound changes with temperature change, which moves rapidly 1190 km / h at sea level, but it drops to 1060 km / h at an altitude of 36,000 feet above the ground, where the air temperature drops. Because the Place de la Concorde to fly faster than the speed of sound, they differ from the rest of the aircraft on several characteristics. First, in terms of the flow of the fuselage, where you need to own dynamic shape to face severe air resistance at these high speeds, and it is achieved by taking the body form of a high pin tapered, triangular wings tilted back, my head and a tail, and an introduction brushes can be moved to the bottom of takeoffs and landings to be able to see the pilot of the corridor, to the top during flight to improve the flow of the fuselage. Amounting to 83 feet and 8 inches tall plane wings in the company "Oarossbesiak" has produced and supplied surfaces work together Kdvh depth, also works differentially Kjnahat. There is no tip installed inside the concavity of the wing, but no spire parties descend and spin at the same time. The second difference is related engines, where the Concorde's engines proved directly in the wings to avoid the use of any parts of the conductive would crash at high speeds, and the engine fitted with a special friendly hotel to exploit the resulting exhaust for initial combustion cycle combustion again mixing with more new fuel to increase efficient engines and power, where this process provides the engine in the final stage of heating fuel for the production of the required additional power for takeoff and the transition from one phase to the heating of supersonic flight, allowing aircraft takeoff speed of 360 km / h. The useful load carried by the Concorde's less than a third of what was done other than in the weight of the jets under the sound, so it was no reduction in the efficiency of the engine, it is actually the difference between profit and loss. Every Concorde has supplied four-engine aircraft, "Snecma Olympus DS 593," the momentum of 17259 kg. The company "Rolls Royce" design engines, which provided all Dagtin separate engine in order to fuel economy. Each engine and also provided additional Aq. Engine reverse payment system is also equipped. On the other hand, the Concorde is distinct from other aircraft fuel tanks and the presence of more and larger, with four engines burn a tremendous amount of kerosene has more than 25 thousand liters per flight hour. However, the fuel tanks lead a purpose whatever else, which is to maintain the equilibrium plane, where the center to raise the plane travels at high speeds for its center of gravity and then you move amounts of fuel between private additional tanks at the front of the plane and the rear to offset that effect, and returned those quantities at low speed in preparation for landing to bring the situation back to its origin. For example, a flight plan requires the distance between Paris and the French coast on the Atlantic equator at less than the speed of sound speed is determined to 0.93 Mach, to be at the height of about 9000 meters, after which the plane begins to jump quickly to reach the speed of take-off and altitude wanted, it performs speed between the two situations difference to a change in the dynamics of the plane to move from the airline less than the sound quickly to other higher speed of sound, and to overcome this situation, the transfer of fuel in an aircraft using a payment of reservoirs located in the introduction to the reservoirs in the system rear. During the transitional situation between the two modes of ex (between Mach 1 and Mach 1.6) increases air resistance sharply, and at this moment is to break the sound barrier. Once access to 1.7 Mach the captain to stop the internal combustion process, after more than a very plane speed of up to Mach 2, or 2200 km / h, more than twice the speed of sound, which represent the target aircraft speed, while the estimated target of 16000 and 18000 meters altitude. But when approaching landing, the fuel will move to the front of the plane, and the concomitant rise in the plane's nose, to land the plane in a scene it looks like a bird landing on the surface of the water. Finally remains the difference in the fuselage coating, where the Concorde is exposed at high speeds to a very large rise in body temperature as a result of increased friction of air molecules, so they coated special material properties and reflective stronger than those in the other aircraft, capable of dispersing such high temperatures . The fuselage itself is made from a special metal is characterized by a greater capacity to withstand the heat and stress resistance resulting from inflation fuselage resulting in turn from high temperature. The speed of the plane have been identified in the horizontal flight Mach 2.2, which is just before the thermal barrier (which is the speed at which if exceeded temperature increases dramatically), but it has identified the chronological age of the structure of 60,000 flight hours. And making the structure of the aluminum-alloy steel by thermal changes from -35 degrees to +120 degrees, as the flight above the speed limit of the plane requires that the structure is made with a mixture of steel and titanium, which means more weight. Fly the Concorde at the highest altitudes of 50,000 feet, where the air is equal to a tenth of what Tsawiyeh at sea density, and the temperature at that very low altitude, and despite all this work ultrasonic motors with high efficiency. According to reports of the pilots can handle the plane easily. The acceleration of the aircraft and transit speeds TransitionAnd what is characterized travel Balkounkord from other aircraft? Accommodate the Concorde for a hundred passengers and crew consists of a pilot and a flight engineer and his assistant in addition to the six hosts. When quitting, the passenger feels strongly pay back as a result of the launch aircraft from sleep to the speed of 362 km / h in just 30 seconds, which is called the Earth's gravitational force, and quickly reach the maximum height of the plane and penetrate the speed of the sound barrier. In all the flight times travelers can know the speed, through a private display panel installed in front of them, and are entitled to see the curve of the globe and Northern Lights because of the high altitude, which is flying the plane. Travelers can also watch the first layer colors of the atmosphere, where the height of the plane boundary between the first two Tbaktah. It takes Atlantic crossing Balkounkord three and a half hours only, while the that time about nine hours in the other underneath the aircraft sounds. And up the Concorde passengers who starts his journey from London at ten thirty in the morning to New York at nine thirty in the morning, before the date of its launch radios. This of course does not mean a retreat in time, but due to time differences and the short flight time! Over the last quarter-century, Concorde was the five weekly flights between Paris and New York in a record speed of less than 4 hours, at which time it cut the best of conventional aircraft, the same distance in 8 hours. He was landing at Kennedy Airport (according to US time) at eight in the morning, and exiting back to France at the eleventh hour before noon, where businessmen French used to negotiate with the Americans their customers at the airport Salons, without having to go to the business and financial district in Manhattan, and then return to Paris the same day. And to what the fate of the Concorde? I tried both the US and Soviet governments (former) develop similar Balkounkord aircraft, but those attempts ended in retreat, either because the magnitude of the required expenditures on the American side, or the occurrence of accidents due to human error on the Soviet side. Some of these Soviet aircraft had stayed (model "T U-144"), as amended to date, but used in air mail services, also placed some of them in museums, while one of them devoted to project Russian joint US. And remained the Concorde, solo travel of passengers faster than the speed of sound even temporarily suspended service to make adjustments after the accident led to an explosion killed one of them and all of them were. In addition, the high run that made the ticket price between Paris, London and New York round-trip $ 10,000, which led to limited use of the rich and famous costs, as well as what caused the noise and pollution, suffered Concorde most suffered from weak passenger demand for flights, in Following the incident, which came under the air France one in Paris in July 2000 to a near Charles de Gaulle airport hotels, which led to the deaths of 109 people on board and four people on the ground. Consequently After some major attended by experts and investigators, scientists, lawyers, artists, religious leaders and industrialists from different generations, between believers technology and Muslims in terms of authority to the modern age and among those who believe that it is necessary to rein in scientific progress and the development of ethical and legal controls him, took the final decision to stop flights Place de la Concorde. In July of 2003, tens of thousands of lovers of the Concorde gathered along the road to Heathrow Airport in the fog of London, the capital, in a bid farewell final before this model withdraw aircraft from service, after it made its first commercial flight in 1976. This has three Concorde planes reviewing the air before landing at Heathrow Airport in a reference to the termination of commercial flights known aircraft at supersonic speed. And charged the British Airways Concorde plane carrying 100 special guest at the final flight, which launched from Kennedy Airport in New York towards London, penetrated the sound barrier for the last time. Upon entering British airspace acceded Two Concord British Airways, one coming from the city of Edinburgh in Scotland, and the other from the Bay of Biscay west of France. Lovers plane Odalla in July of 2003 in Paris, as well as a pool, in the last trip out between Paris and New York, after a 27-year-old was cut where the distance between the two cities in a matter of three hours and a half. Where he lined up more than 250 workers from the maintenance workers bodyguards honor of the plane at Charles de Gaulle airport, with thousands of French gathered on the edge of the airport to see the plane taking off, holding a banner reading "We love you, Concord." The French lines: that the plane Concorde belong to the humanitarian aviation heritage and must therefore provide an opportunity for more people to see it, and added that it would apply to all of the fleet of Air France Concorde aircraft, which will be displayed every aircraft in museums in France, Germany and the United States, such as the Museum aviation and aerospace in the suburb of "Le Bourget" Paris, the Museum of Aviation near the Scottish capital "Edinburgh". Parts of the plane crashed as sold at Christie's for souvenirs to those who died to travel out, varied between the nose of the plane and the door of cabin leadership and a seat pilot and antenna radar warning in which the two motors of the engines and parts of the dashboard to the instructions and cutlery dishwasher ceramic spoons and silver booklet, worth total amounted to 3.29 million euros, went in favor of a charitable institution of the air France is working in the field of care for the poor children. Last auction for the sale of pieces of a British Airways Concorde has also been established. The British and French companies have announced at the beginning of the month of April of the same year 2003, he stopped Concorde flights after the company "Airbus" that produced externa announced: What's next in the field of transport ultrasonic? American company, "Boeing" is currently working on the supersonic jet, is supposed to be placed in service during the coming years, while filling the attention of European rival, "Airbus" accomplish its flagship aircraft, "Airbus A380 (superjumbo) capable of carrying about 800 passengers, which had been achieved in 2007, while scientists tried to Japanese to develop a model of the plane was enable fly twice as fast as the Concorde, but their experience after the plane landed long model briefly after take-off from the site "Woomera" to launch rockets in the desert south of Australia, and it failed within the project included my company, "Mitsubishi heavy Industries" and "Nissan Motor." He held this paradigm of a length of 11 meters on a rocket, Plans for him to be separated from the booster rocket above the ground, and falling faster than twice the speed of sound, but it got out of control since it was launched. It was supposed to reach the aircraft remotely piloted altitude of 20 thousand meters, before Taud.aly ground faster than twice the speed of sound. The goal was to become a plane "NeXT 1" transport aircraft the fastest in the world to succeed Concorde, with the difference that it will be less noise and damaging to the environment and can accommodate up to 300 passengers: Thus crossed another Concorde SST recent trip mounted aboard a ship in the River Thames sailing from London to the Museum of Flight in Edinburgh, after he has made more than eight thousand flight during which 22 thousand and 768 hours and 56 cut-minute flight, the folded thereby separating mythic unique and important commercial aviation history, a supersonic flight, waiting for what the future holds for us of new inventions ?!

Decentralized event ticketing platform on the Stellar Blockchain, enabling secure ticket sales and auctions within a secondary market. Get ready to buy, sell, or bid on tickets seamlessly – make sure your Freighter Wallet is set up!

# 1. MAGENTO 2 MARKETPLACE FACEBOOK LIVECHAT Facebook has taken the world by storm and become an important element in the field of communications. For businesses, Facebook messenger is about connecting businesses with customers. Some businesses are finding that Facebook may even replace their websites. The integration of Facebook Messenger into your marketplace can make the communication in business enhanced remarkably. Using Magento 2 Marketplace Facebook Live Chat Extension, you can easily keep in touch with various of customers at a time. The chatbox of this extension will help you send and receive messages from users instantly. Let's see outstanding advantages of this extension: Unlimited History Chat One step log in with Facebook, not setup requires Familiar chat box with Facebook Messenger Interface Easily enable/disable and configure Chatbox at the backend Unlimited color Show store profile and like button in the chat box Set greeting, upcoming event, store Facebook profile to the chatbox Chat with unlimited customers on Facebook page User Statistic Increase Fanpage View and Like Purchasing [MAGENTO 2 MARKETPLACE FACEBOOK LIVECHAT](https://landofcoder.com/marketplace-facebook-livechat.html/) This is a plugin of [Magento 2 Marketplace Extension](https://landofcoder.com/magento-2-marketplace-extension.html/). To use this module smoothly, you must install Magento 2 Marketplace Module first. ## 2. Documentation - Installation guide: https://blog.landofcoder.com/magento-2-install-extension/ - User guide: http://guide.landofcoder.com/ - Download from our Live site: https://landofcoder.com/magento-2-pre-order-extension.html/ - Get Support: https://landofcoder.ticksy.com/ ## 3. Highlight Features ### One step log in with Facebook Super Fast Logging in Facebook has never been easy like this with Magento 2 marketplace Facebook live chat extension. Type your email address/ your telephone number and your password in the box or if you have not had account, it seems to be simple way to create new account for you. Just by one click on your website, your customer can easily send and receive messages from you. No complicated setup requires. ### Configure all features of Chatbox Appearance of your chatbox plays an important role in how to communicate effectively with your customers. With Magento 2 marketplace facebook live chat extension, creating the best comfortable space for interaction can be optimized. You can change Title/ color/ Text color of tab close, Title/ Unlimited Color/ Width/ Height of Tab Open. Especially, you can even justify your avatar image width/height to raise your customers’impression when communicating with you. ### Get user information In the blink of eye This extension provides you the best management’s system with the board of “Manage data user”. You can keep track of how many people visit, interact in your web and how many people have real interest or enroll to spam. Name, Email, DOB, Location, Link Facebook of register users are now all on your list. ### Set greeting, upcoming event, store Facebook profile Being the first one to welcome your customers in your web can make them feel being respected. You can choose to send messages of greeting, event to customer manually or automatically. What can make them pay attention to is all the information in your web coming to them first. Magento 2 marketplace facebook live chat can help you to update the recent message and upcoming event for your customers or even you can send message to the host of page. ### Show site/product/category on the chat box When receiving a request from the customer, you can send them the site/product/category links in the chatbox. It will be always appear in your screen, so it seems to be very simple to do multitasks: both searching products’information and keeping in touch with the customers. ### Unlimited History Chat The same function as Facebook messenger app, Marketplace facebook live chat extension provides you responsive interface in which you can scroll down or search for any customer in your history no matter when it is. This goes beyond the limitation of current chat desk. If you need to find exact customers to check the exchanged information, you can only search a part of his/her name and the system will send you limited list for you. ### Increase Fanpage View and Like By using Magento 2 Marketplace Facebook Live Chat, you can drive your customer to your Facebook page. Keep theme follow your business all the time with updated news. They will not only interact in your website, but they can also do this in your fanpage on Facebook. ### Multiple and RLT Languages Magento 2 Marketplace Facebook Live Chat do not forget customers who want to use multiple languages or RTL language system. It helps you attract lots of customers without any limitation of cultures and languages.Take it easy for all! ### Familiar chat box with Facebook Messenger Interface With the familiar Facebook Messenger Interface in Magento store, customers and owners can communicate each other with ease. ### Enable/disable the extension by one click Simply to Enable/ Disable Magento 2 Marketplace Facebook Livechat extension for your store in the board of “Facebook support Live settings”. Just one click required! ## 4. Full features: - Easy log in with Facebook - Configure all features of Chatbox - Easy user management - Automatically send greeting and upcoming events notification. - Flexible functions of chatbox. - Unlimited History Chat - Promote interaction on Facebook fanpage - Multiple and RLT Languages - Familiar Facebook messenger interface of chat box - One-click operation of this extension - Show store profile and like button in the chat box - Chat with unlimited customers on Facebook page ## LandOfCoder extensions on Magento Marketplace, Github - [Magento 2 Multivendor Marketplace](https://landofcoder.com/magento-2-marketplace-extension.html/) - [Magento 2 Blog Extension](https://landofcoder.com/magento-2-blog-extension.html/) - [Magento 2 Testimonial Extension](https://landofcoder.com/testimonial-extension-for-magento2.html/) - [Magento 2 Image Gallery](https://landofcoder.com/magento-2-image-gallery.html/) - [Magento 2 Faq Extension](https://landofcoder.com/faq-extension-for-magento2.html/) - [Magento 2 Help Desk](https://landofcoder.com/magento-2-help-desk-extension.html) - [Magento 2 OUT OF STOCK NOTIFICATION](https://landofcoder.com/magento-2-out-of-stock-notification.html/) - [Magento 2 CUSTOMER QUOTATION FOR MAGENTO 2](https://landofcoder.com/magento-2-quote-extension.html/) - [Magento 2 RMA Extension](https://landofcoder.com/magento-2-rma-extension.html/) - [Magento 2 Stripe Payment](https://landofcoder.com/magento-2-stripe-payment-pro.html/) - [Magento 2 SMS Notification](https://landofcoder.com/magento-2-sms-notification-extension.html/) - [Magento 2 Page Builder](https://landofcoder.com/magento-2-page-builder.html/) - [Magento 2 Form Builder](https://landofcoder.com/magento-2-form-builder.html/) - [Magento 2 Advanced Report](https://landofcoder.com/magento-2-advanced-reports.html/) - [Magento 2 Marketplace PRO](https://landofcoder.com/magento-2-marketplace-pro.html/) - [Magento 2 Order Tracking](https://landofcoder.com/magento-2-order-tracking-extension.html/) - [Magento 2 Order Tracking PRO](https://landofcoder.com/magento-2-order-tracking-pro-extension.html/) - [Magento 2 Multiple Flat Rate](https://landofcoder.com/magento-2-multiple-flat-rate-shipping.html/) - [Magento 2 Shipping Per Product](https://landofcoder.com/magento-2-shipping-per-product.html/) - [Magento 2 Social Login](https://landofcoder.com/magento-2-social-login.html/) - [Magento 2 Store Locator](https://landofcoder.com/magento-2-store-locator.html/) - [Magento 2 Auto Search Extension](https://landofcoder.com/magento-2-search.html/) - [Magento 2 Mega Menu](https://landofcoder.com/magento-2-mega-menu.html/) - [Magento 2 Mega Menu PRO](https://landofcoder.com/magento-2-mega-menu-pro.html) - [Magento 2 Image Gallery PRO](https://landofcoder.com/magento-2-image-gallery-pro.html/) - [Magento 2 Layered Navigation](https://landofcoder.com/magento-2-layered-navigation.html/) - [Magento 2 Auction Extension](https://landofcoder.com/magento-2-auction-extension.html/) - [Magento 2 Store Credit](https://landofcoder.com/magento-2-store-credit.html/) - [Magento 2 Reward Point](https://landofcoder.com/magento-2-reward-points.html/) - [Magento 2 Follow Up Email](https://landofcoder.com/magento-2-follow-up-email.html/) - [Magento 2 Coupon Code Generator](https://landofcoder.com/magento-2-coupon-extension.html/) - [Magento 2 Hide Price](https://landofcoder.com/magento-2-hide-price.html/) - [Magento 2 Price Comparison](https://landofcoder.com/magento-2-price-comparison.html/) - [Magento 2 SMTP Extension](https://landofcoder.com/magento-2-smtp-extension.html) - [Magento 2 Price Comparison](https://landofcoder.com/magento-2-price-comparison.html/) - [Magento 2 Affiliate Extension](https://landofcoder.com/magento-2-affiliate-extension.html/) - [Magento 2 One Step Checkout](https://landofcoder.com/magento-2-one-step-checkout.html/) Sources: https://landofcoder.com/marketplace-facebook-livechat.html/

Collectopia is a modern auction and trading platform built with React, Next.js, Node.js, and MongoDB. It offers real-time bidding, secure trades, notifications, and social interactions. With live chats, event tracking, and responsive design, Collectopia is the perfect space for collectors to auction and trade items effortlessly across devices.

This repository houses the front-end client for an online auction project. Built with React and a range of complementary libraries, it enables users to participate in auctions, make bids, and engage in real-time auction events. The project's user interface is enhanced with features like responsive design, real-time updates.

auction events for hsd

Tweets LAND auction events from the Decentraland Marketplace.

El-Marchi: an E-commerce platform dedicated for everything related to trade from online shopping, to big shopping events management and annoucements, online auctions and in person auction events, Map for local markets and their specialities.

DTIX is a full-stack ticket booking application that combines traditional ticketing with blockchain technology. Users can browse events, select seats interactively, and purchase tickets through multiple payment methods (credit cards, MoonPay, HIVE). Key features include NFT ticket minting for authenticity verification, real-time auction rooms

A content management system catering to a local LETS. A full-featured suite of tools to transact, communicate and meet with your community. Submit articles and events, make comments, create auctions and much more!

An auction API project built on the .NET platform during the NLW Expert event.

A comprehensive Discord bot for server management and user engagement. Features include leveling, profile management, event handling, auctions, perks, blacklist, and moderation.

Final Call is a high-performance, broadcast-quality web application designed to bring the excitement of professional sports auctions (like the IPL or NBA drafts) to local tournaments, e-sports events, and corporate leagues.

A mobile auction app built for artists and patrons at art shows. Galeriste enables bidding via QR codes, extending sales beyond the event through a minimalist, intuitive UI.

Upgradeable NFT auction protocol with off-chain event indexer and REST API

A Discord bot to facilitate auctions. It allows users to create auction events, place bids, and manage auction processes seamlessly.

Full-stack auction web application that enables users to create and manage events for auctions.

Graphql server for parsing blockchain events for 2100 token auctions.

Auction Engine on Event Sourcing from Kafka

Send notification to all players when Crazy-Auctions triggers event

Smart contracts for SHOP token and dutch auction public token event

Connect into Handbid's realtime event system for some auction fun times!

This application helps to manage and organize the ESO Guild Auction Events. Created with Ruby on Rails.

This project was game app used in college event infusionX for Cric Auction