Fullstack Engineer / AI Engineer

Braiins Systems · Prague or partially remote from CZ/SK location · Full-time (employee or freelance)

We build the software that runs a meaningful share of the world's Bitcoin mining hardware. Alongside our flagship Braiins OS+ and Braiins Pool (the world's first Bitcoin mining pool), we build Braiins Manager — the cloud platform for remote fleet management — and the desktop tooling that goes with it.

We're looking for a fullstack engineer who is equally comfortable shipping a feature end to end and building the AI tooling the rest of the team develops with. Not a prompt specialist bolted onto a product team — an engineer who happens to be very good at getting real work out of models.

Do you wanna know more about Braiins? Check our Cocuma profile!

⚙️ What you'll actually work on

You'll own features across the full lifecycle: architecture and design, implementation on both sides of the wire, then troubleshooting it in production when a customer with thousands of miners hits an edge you didn't predict.

The platform. A NestJS/TypeScript API on PostgreSQL, with Redis, queue-driven background work (BullMQ, Kafka) and gRPC where devices talk to us. An Angular dashboard, a React desktop frontend, and a Rust daemon in between. It all runs containerised on our own Kubernetes.

The AI half. We run an internal agent platform: a shared library of agent skills and MCP servers wired into our repos, plus an orchestration pipeline that carries a product idea through discovery, design, stories and implementation with a human approval gate at each stage. Real infrastructure with real users — our own team — so it's treated like production: evaluated, versioned, observable, honest about what it can't do. You'd work on agent and tool design, MCP integrations, context engineering, retrieval over our domain data, and the evals that keep it from silently degrading. Where AI belongs in the product itself is still open, and we'd like your help answering it.

You'll join an international, multidisciplinary, fully remote team, with a flat structure and short paths to a decision.

🔍 What we're looking for

• Strong TypeScript, both ends. Node.js on the server (NestJS or equivalent) and a modern SPA framework (Angular, React, Vue). Real depth on one side, genuine competence on the other — we're not looking for someone who "also touches the frontend."

• SQL that goes past the ORM. PostgreSQL, relational modeling, migrations, and the judgement to know when the query builder is the wrong tool.

• Hands-on experience shipping with LLMs. Tool/function calling, MCP, retrieval, agent orchestration, evals — any credible subset. Equally valid: you've pushed coding agents hard enough on real codebases to have opinions about where they break.

• Git, Docker, CI. The daily toolchain, not a checkbox: readable history and clean branches, a service you can containerise yourself, and a pipeline you can fix when it goes red. Kubernetes is a plus, not a gate.

• Comfort with asynchronous, distributed systems. Queues, at-least-once delivery, idempotent handlers, retries and backpressure — and what each of those costs. Microservice architecture, observability stacks, time-series or telemetry data at scale.

• REST and gRPC; a working understanding of what's underneath them.

• Tests you'd defend in review — unit and integration, and the judgement to pick.

• Debugging as a core skill. Reading a stack trace, a slow query plan and a metrics dashboard with equal comfort.

• Solid grasp of algorithms and data structures.

• English at a communicative level, and the self-direction a remote team needs.

✨ Nice to have — genuinely optional

• Rust. We have a real Rust codebase and you can go as deep into it as you want. It is not a requirement and not something we screen on — if you come from C, C++ or Go, or simply want to learn it here, that's a welcome bonus, nothing more.

• Python — our agent orchestration tooling lives there.

• Frontend craft: design systems, accessibility, bundle and rendering performance.

• An interest in Bitcoin or active experience with cryptocurrencies.

🇨🇿 The work is located in Prague, Czech republic. Therefore we are looking for candidates located in this area.

🎉 What we offer

• Full-time position with flexible working hours, employee or freelance.

• On-site, hybrid, partially remote from CZ/SK - due to occasional commuting to office in Prague for meetings.

• Indefinite contract.

• For employees: 5 weeks of vacation and 3 sick days.

• Company events and the occasional Braiins brunch.

• A generous budget for AI tooling, and the freedom to use it properly.

• Long-term work on products used daily by industrial-scale mining operations.

Interested? Tell us what you've built — a repo, a system you're proud of, or an agent setup that actually earns its keep. We'd rather read that than a cover letter.

Do you want know more about Braiins? Check our Cocuma profile!