Available for engagements

Independent Haskell & Backend Engineer

I build production backends, modernize Haskell codebases, and own engagements end-to-end — from domain modeling and API design through deployment and the Linux infrastructure underneath.

Services

Production Haskell

Yesod and Servant services taken from greenfield through deployment, plus modernization and remediation of existing codebases — GHC upgrades, dependency cleanup, performance work, and tightening up the type-level design so the compiler catches bugs instead of production.

Full-Stack Backends

REST and GraphQL APIs in Haskell, TypeScript, and C#, owned end-to-end: schema design, auth and authorization, persistence, background jobs, observability, and the deployment pipeline that ships them. Frontends in React or Next.js when the engagement calls for it.

Domain Modeling

ADT-driven schemas and relational designs that translate stakeholder workflows into systems that hold up under change. I sit with the people who actually do the work, model the invariants explicitly, and make illegal states unrepresentable — so the data layer stops being the source of bugs.

Deployment & Infra

Debian, Nginx, systemd, Docker, Vercel, Supabase, and Azure. I handle the Linux underneath — TLS, reverse proxies, service units, log rotation, backups — so the application I just shipped actually stays up without a separate ops contract.

Currently shipping

AI Integration

Claude and LLM APIs wired into real systems as tool-use assistants — not chatbots bolted on, but structured workflows where the model has typed tools, real data access, and a clear job. Recent work: LifeOS, an executive operations platform where Claude operates across calendar, work items, and life domains.

Recent results

Stack

Languages: Haskell · Rust · TypeScript · Python · C · C# · Lisp/Scheme

Backend: Yesod · Servant · .NET · REST · GraphQL

Frontend: React · Next.js · Tailwind · React Native (Expo)

Infra & Data: Debian · Nginx · systemd · Docker · Vercel · Supabase · Azure · PostgreSQL · MSSQL

Work with me

Currently taking on part-time and project-based engagements. The fastest way to start a conversation is email.

Emailihlopez25@outlook.com

Phone+1 (787) 237-3777

Based inCaguas, Puerto Rico — working remotely

ElsewhereGitHub · LinkedIn

Email me about your project