Available for freelance projects
Mario Martinez
Freelance developer who builds reliable web apps and gets projects shipped, end to end. I build systems that hold up and untangle the problems in between.
Hiring for a full-time role instead? See my resume site →
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What I can help with
Full-stack web apps
End-to-end builds — from data model to deployed product — so you're not juggling multiple contractors to get one thing shipped.
Backend systems & APIs
Real-time features, background jobs, and databases built to stay reliable under load.
API & data integrations
Connecting third-party services, cleaning up messy data pipelines, and automating the manual processes slowing your team down.
Websites & MVPs for small businesses
Get online fast with a site or simple web app built to launch quickly and grow with you.
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Why work with me
I've shipped HIPAA-compliant healthcare tooling, real-time systems, and APIs that keep messy data honest — the kind of work where "it just needs to work" isn't a nice-to-have. The same care goes into freelance projects, whether that's a full build or a focused piece of a larger system.
I run my own self-hosted homelab, so uptime and reliability aren't just résumé words — they're a habit. You get direct communication, no agency layers, and code built to be maintained by someone else after I'm done.
Typical toolset: TypeScript, React, Elixir, Phoenix, PostgreSQL — happy to work in whatever fits the project best.
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Recent track record
Led architecture and delivered a secure, HIPAA-compliant document generation service with zero security incidents, plus a real-time notification system for instant in-app updates.
Built an API to automate importing external patient data and wrote data-cleaning scripts to keep the database free of erroneous records.
Built a microservice for foreign exchange rate estimates and a WebSocket layer for real-time data sync between browser and API.
Full work history available on my resume site →
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What people say
During the past four years, Mario Martinez has been web designer for three of my websites: outofthebluestories.com mirrorsandwindowsworkshop.com, and celebrateinterdependence.com
Mario is talented, hard-working, patient and reliable, with quick turnarounds for all work requests. In addition, he is a pleasure to work with: easy going, affable, intelligent, professional. Without hesitation, I give Mario my highest recommendation.
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Let's work together
Available for freelance projects — reach out with a bit about what you're building and I'll get back to you.
mario@mariobytes.dev Start a project