$1M/day
Multichain Payment Infrastructure
Non-custodial payment system across EVM and Solana. Handles up to $1M/day in transaction volume with gasless flows, wallet integrations, and full monitoring coverage.
BlockchainSolanaEVMNode.jsAWS
semi.engineerproduction systems, shipped
Semi Fernandez
Senior Software Engineer
I build production systems across blockchain, frontend, and backend — and the infrastructure that keeps them running.
$1M+/daytransaction volume
100+integrating teams
53countries
80s → 5sload time fix
What I do
1
Blockchain
EVM · Solana · TON. Multichain infrastructure, wallet integrations, gasless flows, and non-custodial payment systems. Built systems handling $1M/day in transaction volume.
2
Frontend
React · Next.js · TypeScript. I translate complex transaction flows into fast, intuitive interfaces. 80s → 5s load time fix. −50% onboarding churn.
3
Backend
Node.js · AWS (Fargate, SQS, Lambda, Aurora, DynamoDB, Redis). APIs adopted by 100+ integrating teams. End-to-end ownership from architecture to incident response.
4
Other
Teaching at uDevHouse. Smart-contract security reviews. Electronics engineering background. Founder and CTO of two companies.
Selected work
Three proof points from production systems: money moved, teams integrated, people onboarded.
100+ teams
Developer Platform & API
Multi-team API platform and developer tooling adopted by 100+ integrating teams. Full ownership from system design through incident response and on-call.
TypeScriptAWSNode.jsAPI Design
80s to 5s
Global Onboarding System
Rebuilt transaction and onboarding flows across 53 countries. Cut page load from ~80s to 5s and reduced onboarding churn by 50%.
ReactNext.jsTypeScriptPerformance
About
Senior software engineer with 8+ years building production systems across frontend, backend, and blockchain infrastructure. My work has focused on multichain products, payment flows, developer platforms, and wallet-adjacent experiences across EVM, Solana, and other ecosystems.
I bring strong end-to-end ownership, practical product sense, and a bias toward building systems that are both technically sound and usable in the real world.
Engineering career
- Tech Lead/ Vudy2024 – Present
Built product architecture from scratch, owned observability on a live system processing $1M/day, and shipped gasless payment flows across 8+ EVM networks.
- Founder & CTO/ U3 Tech2024 – Present
Web3 payment infrastructure for LATAM businesses. Multichain dApp frontends and backend systems serving users across 53 countries.
- Founder & CEO/ uDevHouse2023 – Present
Engineering education platform for production-grade full-stack and Web3 development. Mentored engineers across frontend, dApp, and smart contract domains.
- Full-Stack & Web3 Engineer/ Freelance2021 – 2023
Shipped features across 10+ production projects — React dApps, wallet integrations, event-driven pipelines, and smart contract security reviews across EVM, Solana, and TON.
- Frontend & Process Developer/ Anywhere Inc.2018 – 2021
Rebuilt core platform workflows and dashboards used across multiple countries, modernizing the frontend with a focus on usability for non-technical stakeholders.
Before software
Before full-time engineering I repaired avionics electronics, designed wireless networks for commercial buildings, helped run a tourism company, and spent two years making coffee.
- Barista/ Guatemala City2009 – 2011
Front-of-house service and coffee craft.
- Electronics Technician/ Avionics Shop~1 year
Electronic component repair and maintenance for aviation equipment.
- Network & Audio Installer/ Independent
Designed and installed enterprise wireless networks for Torre Barcelona and the Condado Naranjo offices in Guatemala City. Multiple private home audio and network installations. Unifi certified.
- Technician/ Auto Shop
Hands-on technical work in an automotive environment.
- Business Development & Data Analyst/ Guatemala Nature Tours
Family-owned tourism company. Built reports, analyzed data, and supported business decisions.
Operating style
How I work
I care about the craft, but I care more about what the craft does for people. The best work feels like a room where everyone gets sharper.
1
Transparency
I share real numbers, real tradeoffs, and real limitations. No inflated claims.
2
Teamwork & mentorship
I enjoy helping people level up, and I expect to be leveled up by the people around me. Strong teams make feedback normal, generous, and useful.
3
Higher purpose
I want the systems I build to matter beyond a dashboard: useful infrastructure for communities, better access for people, and products that improve real lives.
4
Directness
I say what I mean. Clear scope, honest timelines, no fluff in communication.
5
Equality
I've built for 53 countries, mentored engineers across LATAM, and I believe good software should work for everyone.
6
Privacy
I build non-custodial systems and avoid unnecessary data collection — in my products and in my own site.
Open channel
Get in touch
Open to serious product work, Web3 infrastructure, developer platforms, and conversations with builders who care about usefulness, not just noise.