Romania · EU time zone · Available for remote contract work

Cosmin Mare

Full-stack developer. I build web and mobile products with Next.js, React and React Native, from the database to deployment.

Two years of engineering at Hack Club, a US non-profit, plus production sites and admin tools for clients in Romania. I also design hardware, so I'm comfortable where software meets devices.

2 + years shipping production code

3 roles at Hack Club: core team, student programs, European events

1000 + users reached through open-source work

See my work Get in touch

About

I'm Cosmin, a full-stack developer based in Dej, Romania. From 2024 to 2026 I worked at Hack Club, first on the core engineering team, then building programs for students and running its events across Europe.

Alongside that I build production sites and internal tools for clients: content systems that non-technical staff run themselves, database migrations, and deployments that keep working after I hand them over.

I'm looking for a long-term remote contract, 30–40 hours a week, invoiced through my own company. I work in the EU time zone and overlap comfortably with UK and US East Coast hours.

What you get working with me

End-to-end ownership: frontend, backend, data, deployment
Clear written updates and native-level English
Experience in distributed teams across time zones

Case studies

Three projects that show how I work: the problem, what I built, and what changed.

2026Client project

Kindergarten website with a custom admin CMS

Problem: Grădinița Piticot, a kindergarten in Dej, needed a site that staff with no technical background could keep up to date themselves.
What I built: A Next.js site on Firebase with a custom admin panel: protected routes, Firestore and Storage security rules, and editing screens designed for non-technical users. I also handled the public-sector e-invoicing for the contract.
Result: Staff publish their own updates without asking a developer.
Stack: Next.js · Firebase (Firestore, Storage, Functions) · Vercel

piticotdej.ro

2024 – presentMigration · pro bono

Moving an NGO off Azure SQL

Problem: Va Ajutam din Dej, a local NGO, had its members, posts and projects in an Azure SQL database and needed a stack its small volunteer team could run.
What I built: A Node.js import script that moved members, posts and projects into Firestore, a rebuilt Next.js and TypeScript site, Vercel hosting behind Cloudflare DNS, and Google Workspace for Nonprofits for the team's email.
Result: The NGO's data and site now live on Firestore and Vercel, with the team on its own nonprofit Google Workspace.
Stack: Next.js · TypeScript · Node.js · Firestore · Vercel · Cloudflare

vaajutamdindej.ro

2024 – 2025Engineering

Engineering at Hack Club

Context: Hack Club runs coding programs for thousands of teenagers worldwide with a small, fully remote team.
What I did: On the core team, features and maintenance for shared infrastructure. In the Adventures program, interactive programming experiences for students. Web work on the Juice game-jam site and the Sprig console site.
Result: Code used by thousands of students, shipped in an async team spread across time zones.
Stack: React · Node.js · Flutter · Unity · Git

juice.hackclub.com

Experience

Freelance Full-stack developer 2026 – present

Sites and internal tools for clients in Romania, built and invoiced through my own registered company.

Hack Club Regional Manager (Fellow), Europe Nov 2025 – Mar 2026

Ran Hack Club's satellite events across Europe, such as Campfire, working with local organisers.

Hack Club Engineer, Adventures program Mar – Jul 2025

Designed and built interactive programming experiences for students, first as a contractor, then as an intern.

Hack Club Engineer, core team Jun 2024 – Mar 2025

Internship, then contract: features and maintenance on Hack Club's core technical infrastructure.

Recommendation letter from Hack Club and references available on request.

More projects

Hardware, open source and community work.

2026Hardware + app

Skills

Web and mobile

TypeScript, JavaScript, React, Next.js, React Native, Node.js, Firebase (Firestore, Auth, Storage, Functions), Flutter/Dart

Infrastructure

Vercel, Cloudflare, Docker, Linux servers, Git and GitHub Actions

Hardware

PCB design in KiCad and EasyEDA, ESP32 and ESPHome, RP2040, board-level repair

Contact

Tell me about the role or project: the stack, hours per week and start date. I reply within a day.

contact@mare-cosmin.ro