Full Stack Developer specializing in Ruby on Rails, with 4+ years building and scaling production fintech systems (Active Record, Sidekiq, Redis, PostgreSQL) alongside React, React Native, Node.js, JavaScript and TypeScript frontends. Backend owner at Vita Wallet, where I helped scale a platform to $2B+ USD in processed transfers. More recently expanded into Web3: building and auditing Solidity smart contracts, with a security foundation using Foundry, Slither, and Aderyn - usually still wrapped in a Rails backend. Daily user of AI-assisted development tools (Claude Code, Codex). Background also includes 4+ years teaching Full Stack development, JavaScript, Python, and Solidity to large student cohorts, and a Mathematics degree that shapes how I approach problems.
Experience: 3 years
Yearly salary: $84,000
Hourly rate: $45
Nationality: 🇨🇴 Colombia
Residency: 🇨🇴 Colombia
Experience
Full Stack Developer
Vitality+ 2026 - 2026
API integrations (Google Health, Google Calendar) powering AI-driven wellness recommendations in production. Maintained and extended existing platform functionality across backend and mobile (React Native/Expo, NestJS). Used Claude Code (custom agents, skills, git worktrees) daily to accelerate delivery.
Full Stack Engineer
Investment Armendariz 2025 - 2026
Built and maintained a Ruby on Rails admin backend with a Hotwire dashboard for a DeFi governance protocol. Designed, developed, and audited 28 Solidity smart contracts, identifying and mitigating reentrancy and denial-of-service vulnerabilities with Slither and Aderyn, tested with Foundry. Implemented a RAG pipeline with Pinecone and used Claude Code/Codex (custom agents, skills, MCP) daily.
Full Stack Developer (Fintech & Crypto)
Vita Wallet 2021 - 2025
Owned core backend architecture (Ruby on Rails, Active Record, Sidekiq, Redis) for a fintech platform that scaled to over $2B USD in processed transfers. Built payment provider integrations with banks and exchanges (Binance, Circle) across multiple countries, and batch payment infrastructure for enterprise payroll. Wrote automated test suites (RSpec, FactoryBot) and built React/React Native frontend features end-to-end.
Backend Engineer (Freelance)
Freelancer.com 2021 - 2026
Delivered full-stack Ruby on Rails and React projects across multiple industries (healthcare, marketplaces, warehouse management), building RESTful APIs with PostgreSQL and working directly with clients on requirements and scope. Solidity smart contracts (ERC-20/ERC-721) with OpenZeppelin, Hardhat, Truffle, and dApp frontends with Web3.js/Ethers.js/MetaMask.
Full Stack & Blockchain Programming Instructor
Coderhouse 2020 - 2024
Designed and delivered a full stack technical curriculum (React, Node.js, PostgreSQL, REST APIs, blockchain fundamentals) for ~20,000 students across ~80 cohorts, mentoring students through real-world projects and code reviews.
Skills
javascript
math
node
python
react
ruby
solidity
teaching
typescript
