Hire the Best Blockchain Developers
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Francisco B.

Salamanca, Spain

$50/hr
4.7
6 jobs

I'm a freelance Blockchain specialist with over 9 years of experience delivering high-quality decentralized applications, smart contract systems, and Web3 infrastructure. I've worked with a wide variety of clients. From DAOs and startups to established tech companies building: ๐Ÿง  Smart contracts (Solana, Solidity, Hardhat,...) ๐Ÿงฎ DeFi platforms (staking, liquidity mining, fee management, Native DEX,...) ๐Ÿ–ผ๏ธ NFT marketplaces (minting, royalties, IPFS/Pinata, metadata management) ๐ŸŒ‰ Cross-chain tools and integrations (Safe, Aave, Uniswap, Metamask, THORChain, CosmosSDK, IOTA,...) ๐Ÿงฐ Custom tooling and dApp frontends (React, Node.js, TypeScript, Ethers.js, Wagmi, Go,...) I'm also experienced in project leadership and backend systems, which helps me collaborate with full-stack teams, manage timelines, and deliver reliable software even under tight deadlines. โœ… Strong communication โœ… Web3-native mindset โœ… Adaptable to remote teams and async workflows If youโ€™re looking for a committed and hands-on blockchain expert to bring your Web3 product to life, or scale it. Letโ€™s connect.

  • Blockchain
  • Blockchain Architecture
  • Blockchain Development
  • Ethereum
  • JavaScript
  • Python
  • C#
  • Solidity
  • Docker
  • Cryptocurrency
  • Engineering Tutoring
  • C
  • Smart Contract Development
  • Web3
Ignacio P.

Madrid, Spain

$50/hr
5.0
13 jobs

Blockchain engineer, 5 years writing Solidity in production. I've shipped smart contract systems across DeFi, NFTs and L1 consensus, and I build the frontend and backend around them too, so you're not stitching three freelancers together. Systems I've built and shipped: โ€ข Consensus and staking contracts for an L1, audited by a top-tier firm and live on mainnet through a token generation event. Validator committee logic, delegation, reward accounting, plus the foundation vesting schedules around it. โ€ข A community rewards platform with sybil resistance, pluggable quest types, and verification across X, Discord, Telegram and on-chain activity. Processed rewards for 95k+ contributors. โ€ข Token launch infrastructure with custom Uniswap V4 liquidity curves, where each launch spins up its own on-chain economy. โ€ข Gasless wallet UX using embedded wallets, EIP-7702 delegation and ERC-7579 smart accounts. Users tap once and never see a gas prompt or a seed phrase. โ€ข Cross-chain swap integrations across Base, Solana and BNB from a single interface, routed through aggregators. โ€ข DAO treasury and governance contracts, plus ERC-6551 token-bound account identity and dynamic metadata NFTs. โ€ข NFT platforms: upgradeable proxies, Beacon Proxy factories for user-generated collections, Merkle whitelisting, reveal mechanics, marketplace contracts with the backend behind them. On the AI side I build agent systems that actually run something, not demos. Most recent one is a Claude Code workspace running a marketing agency's daily operations: review replies on Google Business Profile and TripAdvisor, monthly Metricool reports delivered over Gmail, automated newsletters. Orchestrated through MCP servers with Playwright as the fallback for platforms with no write API, packaged so non-technical staff install it in one command. I hold an MSc in Machine Learning and AWS ML Specialty certification, so the AI work isn't a recent pivot. What I can take off your plate: โ€ข Smart contract development and refactors: Solidity, Foundry, Hardhat, proxy patterns, ERC-20/721/1155/4626 โ€ข Pre-audit hardening: Slither, fuzz testing, invariant tests, fixing what auditors flagged โ€ข DeFi and protocol integrations: Uniswap V3/V4, 0x, Relay, vesting and staking โ€ข Full-stack dApps: Next.js, React, TypeScript, wagmi/viem, Node.js, Go, PostgreSQL, Docker โ€ข Account abstraction and wallet UX for users who don't want to know they're using crypto โ€ข AI agents and MCP tooling wired into real systems and APIs

  • Blockchain
  • Blockchain Development
  • Ethereum
  • Smart Contract
  • TensorFlow
  • Python
  • Deep Learning
  • Keras
  • Machine Learning
  • JavaScript
  • Cryptocurrency
  • Solidity
Esteban L.

Altea, Spain

$25/hr
5.0
3 jobs

Experienced blockchain developer with strong background in smart contract development, blockchain architecture and backend. Proven ability to implement and test decentralized applications on Ethereum and Hyperledger platforms.

  • Blockchain
  • Ethereum
  • Hyperledger Fabric
  • Golang
  • Node.js
  • JavaScript
  • Git
  • Docker
Aniol C.

Barcelona, Spain

$38/hr
5.0
1 jobs

๐—œ ๐—ต๐—ฒ๐—น๐—ฝ ๐—ฐ๐—ผ๐—บ๐—ฝ๐—ฎ๐—ป๐—ถ๐—ฒ๐˜€ & ๐—ฒ๐—ป๐˜๐—ฟ๐—ฒ๐—ฝ๐—ฟ๐—ฒ๐—ป๐—ฒ๐˜‚๐—ฟ๐˜€ ๐—ฏ๐˜‚๐—ถ๐—น๐—ฑ ๐˜๐—ต๐—ฒ ๐—ฏ๐—ฒ๐˜€๐˜ ๐—ช๐—ฒ๐—ฏ๐Ÿฏ ๐—ฝ๐—ฟ๐—ผ๐—ท๐—ฒ๐—ฐ๐˜๐˜€ ๐—ฎ๐—ป๐—ฑ ๐—•๐—น๐—ผ๐—ฐ๐—ธ๐—ฐ๐—ต๐—ฎ๐—ถ๐—ป ๐—ฏ๐—ฟ๐—ฎ๐—ป๐—ฑ๐˜€ ๐Ÿ“ˆ ๐˜๐—ต๐—ฟ๐—ผ๐˜‚๐—ด๐—ต ๐—ฆ๐—–๐—”๐—Ÿ๐—”๐—•๐—Ÿ๐—˜ ๐—ฑ๐—ฒ๐˜ƒ๐—ฒ๐—น๐—ผ๐—ฝ๐—บ๐—ฒ๐—ป๐˜ ๐—ฎ๐—ป๐—ฑ ๐—ฆ๐—ง๐—ฅ๐—”๐—ง๐—˜๐—š๐—œ๐—– ๐—ฐ๐—ผ๐—ป๐˜€๐˜‚๐—น๐˜๐—ถ๐—ป๐—ด ๐Ÿ”ฅ +175 projects, +20M in revenue, +3M in funds raised ๐—”๐—น๐—น ๐—ผ๐—ณ ๐˜๐—ต๐—ฒ๐—บ ๐˜๐—ฎ๐—ธ๐—ฒ๐—ป ๐˜๐—ต๐—ฟ๐—ผ๐˜‚๐—ด๐—ต ๐—บ๐˜† ๐—”-๐—ญ ๐—ฝ๐—ฟ๐—ผ๐—ฐ๐—ฒ๐˜€๐˜€ ๐˜๐—ผ ๐—ฐ๐—ฟ๐—ฒ๐—ฎ๐˜๐—ฒ ๐˜๐—ต๐—ฒ ๐—ฏ๐—ฒ๐˜€๐˜ ๐˜๐—ฒ๐—ฐ๐—ต๐—ป๐—ผ๐—น๐—ผ๐—ด๐˜† ๐—ฎ๐—ป๐—ฑ ๐—ถ๐—ป๐—ณ๐—ฟ๐—ฎ๐˜€๐˜๐—ฟ๐˜‚๐—ฐ๐˜๐˜‚๐—ฟ๐—ฒ ๐—ฒ๐—ป๐˜€๐˜‚๐—ฟ๐—ถ๐—ป๐—ด ๐˜€๐—ฒ๐—ฐ๐˜‚๐—ฟ๐—ถ๐˜๐˜† & ๐—ฒ๐—ณ๐—ณ๐—ถ๐—ฐ๐—ถ๐—ฒ๐—ป๐—ฐ๐˜†. ๐ŸŽฏ "๐™‰๐™ค ๐™ฆ๐™ช๐™š๐™จ๐™ฉ๐™ž๐™ค๐™ฃ๐™จ ๐™–๐™จ๐™ ๐™š๐™™, ๐™ฉ๐™๐™ž๐™จ ๐™œ๐™ช๐™ฎ ๐™ž๐™จ ๐™ฉ๐™๐™š ๐™—๐™š๐™จ๐™ฉ ๐™ค๐™› ๐™ฉ๐™๐™š ๐™—๐™š๐™จ๐™ฉ. ๐™„ ๐™๐™–๐™ซ๐™š ๐™™๐™ค๐™ฃ๐™š ๐™– ๐™ซ๐™š๐™ง๐™ฎ ๐™ฉ๐™๐™ค๐™ง๐™ค๐™ช๐™œ๐™ ๐™ง๐™š๐™จ๐™š๐™–๐™ง๐™˜๐™ (๐™›๐™ค๐™ง ๐™ฌ๐™š๐™š๐™ ๐™จ!) ๐™ฉ๐™ค ๐™›๐™ž๐™ฃ๐™™ ๐™– ๐™ง๐™š๐™–๐™ก๐™ก๐™ฎ ๐™œ๐™ค๐™ค๐™™ ๐™—๐™ก๐™ค๐™˜๐™ ๐™˜๐™๐™–๐™ž๐™ฃ ๐™™๐™š๐™ซ๐™š๐™ก๐™ค๐™ฅ๐™ฅ๐™š๐™ง, ๐™–๐™ฃ๐™™ ๐™๐™š ๐™š๐™ญ๐™˜๐™š๐™š๐™™๐™š๐™™ ๐™ข๐™ฎ ๐™š๐™ญ๐™ฅ๐™š๐™˜๐™ฉ๐™–๐™ฉ๐™ž๐™ค๐™ฃ๐™จ 1000%. ๐™‰๐™ค๐™ฉ ๐™ค๐™ฃ๐™ก๐™ฎ ๐™๐™š ๐™ž๐™จ ๐™ซ๐™š๐™ง๐™ฎ ๐™ฅ๐™ง๐™ค๐™›๐™š๐™จ๐™จ๐™ž๐™ค๐™ฃ๐™–๐™ก ๐™–๐™ฃ๐™™ ๐™จ๐™ ๐™ž๐™ก๐™ก๐™š๐™™ ๐™ฌ๐™๐™š๐™ฃ ๐™ž๐™ฉ ๐™˜๐™ค๐™ข๐™š๐™จ ๐™ฉ๐™ค ๐™˜๐™ช๐™จ๐™ฉ๐™ค๐™ข๐™ž๐™ฏ๐™š ๐™จ๐™ข๐™–๐™ง๐™ฉ ๐™˜๐™ค๐™ฃ๐™ฉ๐™ง๐™–๐™˜๐™ฉ๐™จ, ๐™ข๐™ž๐™ฃ๐™ฉ๐™ž๐™ฃ๐™œ ๐™ฌ๐™š๐™—๐™จ๐™ž๐™ฉ๐™š๐™จ, ๐™—๐™ช๐™ก๐™  ๐™ช๐™ฅ๐™ก๐™ค๐™–๐™™๐™จ ๐™ฉ๐™ค ๐™ค๐™ฅ๐™š๐™ฃ๐™จ๐™š๐™–, ๐™จ๐™š๐™ฉ๐™ฉ๐™ž๐™ฃ๐™œ ๐™จ๐™š๐™ง๐™ซ๐™š๐™ง๐™จ ๐™š๐™ฉ๐™˜, ๐™—๐™ช๐™ฉ ๐™๐™š ๐™ž๐™จ ๐™–๐™ก๐™จ๐™ค ๐™ซ๐™š๐™ง๐™ฎ ๐™ฃ๐™ž๐™˜๐™š, ๐™ฅ๐™–๐™ฉ๐™ž๐™š๐™ฃ๐™ฉ, ๐™–๐™ฃ๐™™ ๐™๐™š๐™ก๐™ฅ๐™จ/๐™›๐™ž๐™ญ๐™š๐™จ/๐™–๐™™๐™Ÿ๐™ช๐™จ๐™ฉ๐™จ ๐™™๐™ช๐™ง๐™ž๐™ฃ๐™œ ๐™ฉ๐™๐™š ๐™ฌ๐™๐™ค๐™ก๐™š ๐™ฅ๐™ง๐™ค๐™˜๐™š๐™จ๐™จ. ๐™„ ๐™๐™ž๐™ง๐™š๐™™ ๐™– ๐™™๐™ค๐™ฏ๐™š๐™ฃ ๐™ฅ๐™š๐™ค๐™ฅ๐™ก๐™š ๐™›๐™ค๐™ง ๐™ข๐™ฎ ๐™‰๐™๐™ ๐™ฅ๐™ง๐™ค๐™›๐™š๐™˜๐™ฉ, ๐™–๐™ฃ๐™™ ๐™ฉ๐™๐™ž๐™จ ๐™ฌ๐™–๐™จ ๐™—๐™ฎ ๐™›๐™–๐™ง ๐™ข๐™ฎ ๐™œ๐™ง๐™š๐™–๐™ฉ๐™š๐™จ๐™ฉ ๐™š๐™ญ๐™ฅ๐™š๐™ง๐™ž๐™š๐™ฃ๐™˜๐™š. ๐™๐™๐™–๐™ฃ๐™ ๐™จ ๐™– ๐™ก๐™ค๐™ฉ ๐˜ผ๐™ฃ๐™ž๐™ค๐™ก ๐Ÿ˜€" โญ๏ธโญ๏ธโญ๏ธโญ๏ธโญ๏ธ ๐Ÿ—ฃ Tom Olssen - Vengeaful Beasts ๐Ÿ—ฃ ๐—Ÿ๐—ถ๐—ธ๐—ฒ ๐˜„๐—ต๐—ฎ๐˜ ๐˜†๐—ผ๐˜‚โ€™๐—ฟ๐—ฒ ๐—ต๐—ฒ๐—ฎ๐—ฟ๐—ถ๐—ป๐—ด? ๐—œ๐—ป๐˜ƒ๐—ถ๐˜๐—ฒ ๐—บ๐—ฒ ๐˜๐—ผ ๐˜†๐—ผ๐˜‚๐—ฟ ๐—ท๐—ผ๐—ฏ ๐—ผ๐—ป ๐—จ๐—ฝ๐˜„๐—ผ๐—ฟ๐—ธ ๐˜๐—ผ ๐˜€๐—ฐ๐—ต๐—ฒ๐—ฑ๐˜‚๐—น๐—ฒ ๐—ฎ ๐—™๐—ฅ๐—˜๐—˜ ๐—ฑ๐—ถ๐˜€๐—ฐ๐—ผ๐˜ƒ๐—ฒ๐—ฟ๐˜† ๐—ฐ๐—ฎ๐—น๐—น ๐˜๐—ผ ๐—ณ๐—ถ๐—ป๐—ฑ ๐—ผ๐˜‚๐˜ ๐—ถ๐—ณ ๐˜„๐—ฒ ๐—ฐ๐—ฎ๐—ป ๐—ฏ๐˜‚๐—ถ๐—น๐—ฑ ๐˜€๐—ผ๐—บ๐—ฒ๐˜๐—ต๐—ถ๐—ป๐—ด ๐—ฎ๐—บ๐—ฎ๐˜‡๐—ถ๐—ป๐—ด ๐˜๐—ผ๐—ด๐—ฒ๐˜๐—ต๐—ฒ๐—ฟ. ๐Ÿ”Ž ๐—›๐—ฒ๐—ฟ๐—ฒโ€™๐˜€ ๐˜„๐—ต๐—ฎ๐˜ ๐˜€๐—ฒ๐˜๐˜€ ๐—บ๐—ฒ ๐—ฎ๐—ฝ๐—ฎ๐—ฟ๐˜ ๐—ณ๐—ฟ๐—ผ๐—บ ๐—ฎ๐—ป๐˜†๐—ผ๐—ป๐—ฒ ๐—ฒ๐—น๐˜€๐—ฒ ๐˜†๐—ผ๐˜‚ ๐—ฐ๐—ผ๐˜‚๐—น๐—ฑ ๐—ต๐—ถ๐—ฟ๐—ฒ ๐˜๐—ผ ๐—ต๐—ฒ๐—น๐—ฝ ๐˜†๐—ผ๐˜‚: ๐Ÿ”ธ I deliver exceptional results from the start. Many clients reach out to me after trying less experienced talent or in-house solutions that didnโ€™t meet their expectations. By choosing me, youโ€™re securing a product that will make you proud and run smoothly for years to come. ๐Ÿ”ธ Youโ€™re never reliant on me to stay in control! My development approach emphasizes clear, ongoing communication and transparency. I ensure that you have full ownership and understanding of everything built. ๐Ÿ”ธ Working closely with Blockchain companies has allowed me to establish exclusive partnerships with some of the most prominent names in the Web3 industry. From Marketing, PR, Go-to-Market Strategy, and Tokenomics to NFT Strategy, Legal Structure Setup, VC Fundraising, and KOL, I offer comprehensive expertise. ๐Ÿ”ธ Security is never compromised. Too many times in the Web3 world we see projects getting shattered - funds stolen, servers crashing, trust from users lost. Thatโ€™s why I include thorough quality assurance testing at every stage, with final checks before your product is delivered. ๐—œ๐—ป๐˜ƒ๐—ถ๐˜๐—ฒ ๐—บ๐—ฒ ๐˜๐—ผ ๐˜†๐—ผ๐˜‚๐—ฟ ๐—ท๐—ผ๐—ฏ ๐—ผ๐—ป ๐—จ๐—ฝ๐˜„๐—ผ๐—ฟ๐—ธ ๐˜๐—ผ ๐˜€๐—ฐ๐—ต๐—ฒ๐—ฑ๐˜‚๐—น๐—ฒ ๐—ฎ ๐—™๐—ฅ๐—˜๐—˜ ๐—ฑ๐—ถ๐˜€๐—ฐ๐—ผ๐˜ƒ๐—ฒ๐—ฟ๐˜† ๐—ฐ๐—ฎ๐—น๐—น ๐˜๐—ผ ๐—ณ๐—ถ๐—ป๐—ฑ ๐—ผ๐˜‚๐˜ ๐—ถ๐—ณ ๐˜„๐—ฒ ๐—ฐ๐—ฎ๐—ป ๐—ฏ๐˜‚๐—ถ๐—น๐—ฑ ๐˜€๐—ผ๐—บ๐—ฒ๐˜๐—ต๐—ถ๐—ป๐—ด ๐—ฎ๐—บ๐—ฎ๐˜‡๐—ถ๐—ป๐—ด ๐˜๐—ผ๐—ด๐—ฒ๐˜๐—ต๐—ฒ๐—ฟ. ๐Ÿ”Ž ๐—ฆ๐—˜๐—ฅ๐—ฉ๐—œ๐—–๐—˜๐—ฆ & ๐—ฆ๐—ข๐—Ÿ๐—จ๐—ง๐—œ๐—ข๐—ก๐—ฆ: โœ… Ethereum / Solana / BSC / Polygon (EVM) Customized Smart Contract Development โœ… Blockchain & Web3 Consultation (Smart Contract Ecosystem Design, Tokenomics, Whitepaper) โœ… EVM Smart Contract Audits (Automated Testing, Security Breach Search, Gas Efficiency, etc.) โœ… NFT Collection (ERC721 / ERC721A / ERC1155) creation (Whitelist, Shareholder Dividends, Burn mechanism, Reveal/Unreveal, Access Control, etc.) โœ… NFT Minting Dapps โœ… NFT Staking Contracts + Staking Dapps โœ… ERC20 Tokens (Basic Tokenomics, Staking Features, Buy Limits, Fees, etc.) + ICOs / IDOs โœ… DAOs โœ… NFT Marketplace โœ… Decentralized Exchange (Uniswap / Pancakeswap) โœ… Launchpad (Seedify) โœ… Yield Farming + DeFi Protocol โœ… Image & Metadata Generation Algorithm for NFT Artwork + IPFS Upload โœ… Solana NFT Smart Contract + Minting Dapp (Candymachine, Metaplex) โœ… 2D & 3D Graphic Design, Animations, and Promo Teaser Videos ๐—ง๐—˜๐—–๐—› ๐—ฆ๐—ง๐—”๐—–๐—ž: โœ… Solidity, Hardhat / Truffle / Remix, Slither, Ethereum / Binance / Polygon / Avalanche / Optimism / Solana โœ… React.JS + Next.JS (Web3.JS, ethersJS), AngularJS, HTML, CSS & JavaScript (jquery, Bootstrap) โœ… Node.js, NestJS, ExpressJS, Docker, Python, Amazon AWS, MongoDB, MySQL โœ… Figma, AdobeXD, PSD โœ… Github / Gitlab / Bitbucket, Slack, Trello / Notion / Clickup / Jira ๐—œ๐—ป๐˜ƒ๐—ถ๐˜๐—ฒ ๐—บ๐—ฒ ๐˜๐—ผ ๐˜†๐—ผ๐˜‚๐—ฟ ๐—ท๐—ผ๐—ฏ ๐—ผ๐—ป ๐—จ๐—ฝ๐˜„๐—ผ๐—ฟ๐—ธ ๐˜๐—ผ ๐˜€๐—ฐ๐—ต๐—ฒ๐—ฑ๐˜‚๐—น๐—ฒ ๐—ฎ ๐—™๐—ฅ๐—˜๐—˜ ๐—ฑ๐—ถ๐˜€๐—ฐ๐—ผ๐˜ƒ๐—ฒ๐—ฟ๐˜† ๐—ฐ๐—ฎ๐—น๐—น ๐˜๐—ผ ๐—ณ๐—ถ๐—ป๐—ฑ ๐—ผ๐˜‚๐˜ ๐—ถ๐—ณ ๐˜„๐—ฒ ๐—ฐ๐—ฎ๐—ป ๐—ฏ๐˜‚๐—ถ๐—น๐—ฑ ๐˜€๐—ผ๐—บ๐—ฒ๐˜๐—ต๐—ถ๐—ป๐—ด ๐—ฎ๐—บ๐—ฎ๐˜‡๐—ถ๐—ป๐—ด ๐˜๐—ผ๐—ด๐—ฒ๐˜๐—ต๐—ฒ๐—ฟ. ๐Ÿ”Ž

  • Blockchain
  • Blockchain Architecture
  • Blockchain Development
  • Ethereum
  • Smart Contract
  • Next.js
  • React
  • Cryptocurrency
  • Node.js
  • JavaScript
  • Python
  • Solana
  • Solidity
  • NFT
  • API
Sergey C.

Barcelona, Spain

$40/hr
4.9
30 jobs

โ—๏ธ๐—š๐—ฒ๐˜ ๐—ฎ ๐—™๐—ฅ๐—˜๐—˜ ๐Ÿ’๐ŸŽ-๐—บ๐—ถ๐—ป๐˜‚๐˜๐—ฒ ๐—•๐—น๐—ผ๐—ฐ๐—ธ๐—ฐ๐—ต๐—ฎ๐—ถ๐—ป ๐—–๐—ผ๐—ป๐˜€๐˜‚๐—น๐˜๐—ฎ๐˜๐—ถ๐—ผ๐—ปโ—๏ธ Iโ€™m a senior blockchain engineer focused on building and scaling production-grade Web3 systems, from smart contracts to full DeFi architectures and backend integrations. I collaborate with security auditors (including Certik) on selected projects when formal audit stage is required, but my main focus is clean architecture, secure contract design, and long-term maintainability before audit even becomes necessary. ๐Ÿ† Blockchain Expertise 11+ years building Web3 infrastructure, including: Smart contract development (Solidity, Rust, Move) Tokenomics & stablecoin architecture DeFi protocols: staking, liquidity pools, AMMs, lending/borrowing Wallet & blockchain integration Cross-chain bridges & interoperability Security audits, gas optimization, and threat analysis Node setup, backend APIs, indexing & on-chain data pipelines ๐—›๐—ถ๐—ด๐—ต๐—น๐—ถ๐—ด๐—ต๐˜๐—ฒ๐—ฑ ๐—ฃ๐—ฟ๐—ผ๐—ท๐—ฒ๐—ฐ๐˜๐˜€: Gold-backed Stablecoin System (Liechtenstein Launch) โœ” KYC onboarding, Sumsub integration โœ” Smart contracts on Ethereum + Polygon โœ” Oracle pricing + OTC gold price feeds โœ” Token mint/burn mechanics โœ” Reserve-backed auditing model โœ” Whitelist & transfer-restriction compliance โœ” Storage-fee mechanism (token balance decay) โœ” Full on-chain/off-chain architecture DeFi Protocols (AMMs, staking, farming) โœ” Smart-contract suite (Solidity) โœ” Reward distribution mechanisms โœ” Price oracle integration (Chainlink) โœ” Security hardening & audit fixes NFT platforms & minting engines โœ” ERC-721 / 1155 collections โœ” Royalty logic, metadata generation โœ” Claiming contracts, allowlists, randomness ๐—•๐—น๐—ผ๐—ฐ๐—ธ๐—ฐ๐—ต๐—ฎ๐—ถ๐—ป ๐—ง๐—ฒ๐—ฐ๐—ต ๐—ฆ๐˜๐—ฎ๐—ฐ๐—ธ: Smart Contracts: Solidity, Rust (Solana), Move (Aptos/Sui) Frameworks: Hardhat, Foundry, Truffle, Anchor Security: Slither, Mythril, Echidna, Certora On-Chain Data: TheGraph, SubQuery, custom indexers Blockchains: Ethereum, Polygon, BNB Chain, Arbitrum, Optimism, Avalanche, Solana, TON Backend: Node.js, NestJS, PostgreSQL, Redis, Docker Tools: Chainlink, Safe (Gnosis), IPFS, Pinata, Fireblocks Want a secure, scalable blockchain product, not a risky MVP? Send the documentation, and letโ€™s build it correctly from day one. ๐—ž๐—ฒ๐˜†๐˜„๐—ผ๐—ฟ๐—ฑ๐˜€: Blockchain, Web3, Blockchain Developer, Web3 Developer, Smart Contract Developer, Solidity Developer, Rust Developer, Move Developer, Ethereum Developer, DeFi Developer, Smart Contract Audit, Security Audit, Tokenomics, Stablecoin Development, NFT Development, ERC20, ERC721, ERC1155, Solidity Engineer, Blockchain Architecture, DApp Backend, Oracle Integration, Chainlink, Hardhat, Foundry, Web3 Security, Multi-Chain Deployment, DeFi Protocol, Yield Farming, Staking Contract, Vesting Contract, Governance Token, On-Chain Data, TheGraph, EVM Developer, Crypto Developer, Blockchain Consultant, Token Development, ICO/IDO Smart Contracts, Bridge Development, Layer 2 Developer, Polygon, Arbitrum, Optimism.

  • Blockchain
  • Blockchain Architecture
  • Blockchain Development
  • Ethereum
  • Smart Contract
  • JavaScript
  • Solana
  • Python
  • web3.js
  • Rust
  • Solidity
  • Node.js
  • Cryptocurrency
  • React
  • HTML
Ruslan K.

Barcelona, Spain

$40/hr
4.9
76 jobs

Iโ€™m a senior Shopify App Developer, MERN specialist, and full-stack developer with 10+ years of experience in Shopify, Shopify Plus, custom apps, public apps, private apps, API integrations, data migration, and complex eCommerce systems. As a Shopify App Developer, full-stack developer, web developer, react developer, python developer, wordpress developer, and blockchain developer, I build stores, apps, dashboards, and workflows that are fast, stable, scalable. ๐Ÿš€ Full-Cycle Shopify, MERN, and App Development. As a Shopify App Developer and full-stack developer, I donโ€™t just write code. I build eCommerce systems that support real business operations. Whether you need a Shopify app, Shopify Plus customization, Shopify data migration, admin tools, public app development, private app development, shopify speed improvement, dropshipping setup, automation, or technical support, I can help from planning to launch. My main focus is Shopify App Developer work, MERN development, full-stack developer solutions, and scalable systems for brands that need clean code, better UX, backend logic, and conversion. I also support web developer tasks, react developer work, python developer scripts, wordpress developer projects, blockchain developer features, mern stack apps, React interfaces, Node.js backends, MongoDB databases, and API integrations. ๐Ÿ’ป Core Expertise - Shopify App Developer services for custom Shopify apps, public apps, private apps, and embedded apps - Shopify App Developer support for Shopify Plus workflows, checkout logic, admin tools, subscriptions, and B2B features - Shopify App Developer integrations with APIs, ERPs, CRMs, payments, fulfillment tools, and analytics platforms - MERN and mern stack development using MongoDB, Express.js, React, and Node.js - full-stack developer support for frontend, backend, databases, cloud services, and deployment - full stack developer architecture for dashboards, portals, SaaS tools, and internal systems - react developer work for storefronts, app interfaces, Polaris components, and interactive UI - React development with Redux, TypeScript, JavaScript, HTML, CSS, SCSS, and component logic - python developer support for data migration, scripts, automation, backend tools, and API workflows - wordpress developer support for WooCommerce, WordPress migration, plugin logic, and frontend fixes - web developer support using HTML, CSS, JavaScript, Liquid, PHP, Laravel, APIs, and cloud tools - blockchain developer support for wallet flows, Web3 integrations, NFT logic, and token-gated features โญ How I Can Help If you need a Shopify App Developer to build a custom app, I can plan the logic, design the architecture, develop the interface, connect APIs, test the workflow, and prepare the app for real use. If you need a MERN developer or mern stack expert, I can build web apps with React, Node.js, Express, and MongoDB. If you need a full-stack developer or full stack developer for an eCommerce platform, I can connect frontend, backend, database, and integrations into one stable system. I can also help as a react developer for clean interfaces, as a python developer for scripts and automation, as a wordpress developer for migration and WooCommerce support, as a web developer for theme and frontend work, and as a blockchain developer for Web3 features. My Shopify App Developer experience also covers app migration, debugging, webhooks, billing logic, product sync, order sync, customer sync, inventory sync, and dashboards. ๐ŸŽฏ My Approach Every project starts with understanding your store, business model, app logic, customer journey, data structure, and technical constraints. As a Shopify App Developer, MERN engineer, full-stack developer, full stack developer, react developer, python developer, wordpress developer, web developer, and blockchain developer, I focus on stable architecture, clean development, QA, and simple handoff. For Shopify projects, I check app logic, Shopify API limits, webhook flows, data migration risks, checkout behavior, speed issues, and conversion gaps. For MERN and mern stack projects, I focus on React structure, Node.js backend logic, MongoDB data design, API security, deployment, and scalability. For full-stack developer and full stack developer tasks, I make sure frontend, backend, database, and integrations work together without fragile shortcuts. Clients choose me because I combine Shopify App Developer experience, MERN execution, full-stack developer thinking, full stack developer flexibility, and real eCommerce understanding. If you need a reliable Shopify App Developer, MERN specialist, full-stack developer, full stack developer, mern stack engineer, react developer, React expert, python developer, wordpress developer, web developer, blockchain developer, Shopify data migration specialist, custom app builder, API integration expert, or eCommerce technical partner, lets discuss.

  • Node.js
  • JavaScript
  • CSS
  • HTML
  • WordPress
  • CSS 3
  • React
  • TypeScript
  • Shopify
  • MongoDB
  • React Native
  • Software Debugging
  • App Development
  • Figma
  • Laravel
  • API Integration
  • MERN Stack
  • Ecommerce
  • Shopify Plus
  • PHP

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