I’m looking for a remote Frontend-focused Full Stack Blockchain role where I can build polished React/Next.js products, Web3 interfaces, wallet integrations, fintech features, and smart contract-connected applications with strong testing, security, and production reliability.
Open to opportunities
Julian Ruiz
@julianruiz
Frontend-focused Full Stack Blockchain Engineer building React, Next.js, Web3 apps, smart contracts, and production-ready products.
ColombiaWhat I'm looking for
I’m a Frontend-focused Full Stack & Blockchain Engineer with 6+ years of experience building production web applications, React/Next.js interfaces, Web3 frontends, fintech products, backend APIs, and smart contract integrations.
My strongest work is on the frontend and product layer: building scalable user-facing applications, dashboards, authentication flows, payment interfaces, wallet-connected experiences, Web3 interaction flows, and maintainable React/TypeScript architectures. I work with React, Next.js, TypeScript, JavaScript, TailwindCSS, React Native, REST APIs, PostgreSQL workflows, Node.js services, and third-party integrations.
At Vita Wallet, I contributed to fintech and crypto product features across React/React Native applications, payment workflows, Binance-related integrations, backend services, PostgreSQL flows, testing, debugging, production support, and platform reliability.
On the blockchain side, I build and integrate Solidity smart contracts using Foundry, Hardhat, OpenZeppelin, wagmi, viem, Ethers.js, MetaMask, RainbowKit, and modern Web3 tooling. My experience includes wallet integrations, DeFi workflows, governance systems, vault and treasury features, NFT platforms, JSON-RPC integrations, fuzz testing, invariant testing, mainnet fork testing, Slither, and Aderyn.
I’m especially interested in remote roles where I can help teams build polished frontend experiences for fintech, Web3, DeFi, payments, and blockchain products, while also contributing to smart contract integration, testing, security, and production-ready delivery.
Experience
Work history, roles, and key accomplishments
IA
Current
Full Stack Blockchain Engineer
Investment Armendariz
Aug 2025 - Present (10 months)
Built Web3-enabled fintech features across React and TypeScript, integrating smart contracts and protocol workflows into scalable application architecture. Developed and tested Solidity contracts and supported secure testing/security workflows including fuzzing, invariants, and mainnet fork testing.
HE
Current
Technical Instructor
Henry
Jan 2023 - Present (3 years 5 months)
Mentored students in full stack projects covering backend architecture, REST APIs, frontend development, authentication, debugging, and scalable application workflows. Provided technical guidance on maintainable development practices and frontend/backend integration.
FR
Current
Freelance Full Stack & Web3 Developer
Freelance
Dec 2021 - Present (4 years 6 months)
Designed and delivered full stack web applications and Web3-enabled products with backend APIs, real-time features, database workflows, and third-party integrations. Developed Solidity smart contracts and dApps using Hardhat/Foundry, integrating wallet connectivity and blockchain SDKs.
VW
Full Stack Developer
Vita Wallet
Oct 2021 - Nov 2025 (4 years 1 month)
Contributed to a global fintech platform operating in 190+ countries and processing over $3B USD annually by building and maintaining frontend, backend, and REST API features for payments and transaction workflows. Improved reliability through testing, debugging, production support, and performance optimizations across integrated payment and crypto services.
HE
Blockchain Exchange & Integration Dev
Henry
Apr 2021 - Jul 2021 (3 months)
Developed a fiat/crypto asset exchange platform with real-time transaction flows and secure blockchain-backed interactions. Implemented frontend/backend integrations using React, Node.js/Express, Supabase persistence, WebSockets, and Stellar SDK.
Education
Degrees, certifications, and relevant coursework
CU
Cyfrin Updraft
Smart Contract Security, Blockchain Security
2024 - 2025
Completed the Cyfrin Updraft Smart Contract Security program (2024–2025).
LC
London School of Commerce
English Language and Literature, English Language & Literature
Studied English Language and Literature at London School of Commerce (2025).
Platzi
Blockchain and Cryptocurrency School, Blockchain & Cryptocurrency
2021 - 2022
Completed Platzi's Blockchain and Cryptocurrency studies (2021–2022).
Henry
Full Stack Developer Program, Full Stack Development
Completed the Henry Full Stack Developer Program (2021).
ITM University
Telecommunications Technology, Telecommunications Technology
2008 - 2011
Studied Telecommunications Technology at ITM University from 2008 to 2011.
CC
CENSA Colombia
English B2, English
Achieved an English B2 level at CENSA Colombia (year not provided).
Tech stack
Software and tools used professionally
Availability
Open to opportunities
Location
ColombiaAuthorized to work in
Portfolio
github.com/MJULIAN90Social media
Job categories
Skills
ReactNext.jsTypeScriptJavaScriptJavaScript (Node.JsREST APIsReact NativeTailwindCSSHTML5CSS3PostgreSQLMicroservicesAuthenticationDatabase DesignQuery OptimizationThird Party IntegrationsJSON RPCWebSocketsSolidityFoundryHardhatERC20ERC721ERC 4626DeFiGovernanceVault ArchitectureMetaMaskIPFSUnit TestingIntegration TestingFuzz TestingInvariant Based TestingStateful TestingMainnet Fork TestingSlitherAderynDebuggingRoot Cause AnalysisPerformance ImprovementWagmiViemPayment InfrastructureWorkflowsPayment IntegrationBinance Related IntegrationsBlockchain IntegrationsOperational SupportReliabilityBlockchainGitHubJSONRoot CauseEthersJSNodeJSRainbow Kit Remote
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