Position: Middle / Senior Blockchain Developer (Solidity)
Company: IOWN Group
Experience required: 3y
English level: upper

**ROLE AND RESPONSIBILITIES**

• Implement/maintain the existing company/clients’ Smart Contracts (release upgrades, provide statistical data, troubleshoot transactions etc.).
• Implement enterprise level Smart contracts for clients to serve specific business requirements and provide blockchain services to clients’ applications.
• Execute customized Smart Contracts which serve as proof of an off-chain activity on chain and use the implementation as proof for performing other actions (e.g., proof that a KYC action was done for a token AirDrop or a Crowdsale Smart Contract).
• Implement Oracle logic allowing creation of contracts for fiat-crypto price tickers or similar logic.
• Deploy smart contracts in a systematic way (truffle or similar) which can be reused in CI/CD pipelines for testing purposes (like on Ropsten, or BSC Testnet).
• Execute Multi Chain bridging and wrapped tokens or integrate L2 solutions to solve gas related issues.
• Implement unit testing and mocking of smart contract logic or activities and provide results/reports to QA engineers.
• Analyze gas usage of Smart Contracts and contract function calls and assist app developers to calculate transaction fees cross different blockchains for internal wallet application.
• Research updates and security issues appearing with different EIPs and their implementations, like double spending problems, re-entrant code and similar, and suggest possible remediations.
• Research compatibility of certain Smart Contracts implementations with 3rd party services (other blockchains, other Smart Contracts or services) such as decentralized exchanges.
• Implement/Integrate webhooks or push notifications with backend developers to feed data from blockchain transactions to systems such as Events emitted during transaction mining, or notifications that a wallet has received tokens (sample tools: Eventeum).
• Execute scripted actions on blockchains for bulk action execution, market making or similar.

**QUALIFICATIONS AND EDUCATION REQUIREMENTS**

• Bachelors’ Degree or higher in Information Technology related studies.
• A minimum of 4 years’ experience developing enterprise applications.
• A minimum of 2 years’ experience with Solidity and writing Smart Contracts, preferably non-ERC20 tokens.
• Level 3 English or higher (reference here: Grammarly Levels).
• Experience with blockchain development tools and services, such as Truffle, Blockchain Transaction Scanners, Remix IDE, Solhint, and similar.
• Experience with Blockchain Gas estimation endpoints (like Etherscan gas oracle API and EtherGasStation) and calculating gas in different blockchains and forks (like London fork for Ethereum).
• Familiarity with transaction receipts and logs, and how to decode events and revert reasons form them.
• Skilled in setting up blockchain nodes particularly Ethereum based, such as Geth, Parity, Ganache, and similar.
• Experience writing Smart Contract unit test and executing tests on deployed Smart Contracts (using truffle migrations, Remix and/or scripting).
• Skilled in writing scripts to read transactions, write transactions, check node status, check DEX liquidity pools and similar using Bash, Python, or any scripting/programming language.
• Understanding of MultiSignature wallets/Multisig Smart Contracts and how Multisig works in general.
• Familiarity with DEXs like Uniswap and Pancakeswap and how liquidity pools are created, and liquidity is added/removed, and how trenches work.
• Understanding modern and trending topics related to blockchain like Stablecoins, NFTs, Asset-backed tokens etc.

**PREFERRED SKILLS**

• Experience with Solidity security and auditing tools like “MythX”, “Mithril”, “MadMax”, “Manticore” and similar.
• Skilled in setting up blockchain webhooks with tools like Eventeum for Ethereum.
• Experience working with different blockchains using Bridges and provide interoperability between Public blockchains (like Ethereum) and Private/Permissioned ones (like Hyperledger fabric).

**ADDITIONAL NOTES**

• Please provide Code Sample - GitHub account, Stackoverflow public profile etc. (If NDA protected, please provide ANY code. The purpose is to check the structure, logging, documentation, error handing...etc.)