Senior Backend Engineer (Node.js)

About us

We’re just 1 year old, already 40 people, and growing quickly. Our slot games are played by more than 1 million people every month, and this is only the beginning.

What we do

Each spin passes through our backend: the game math decides the outcome, a transaction moves the balance, promo features kick in, and analytics records it. It all has to be correct, fast and ready for traffic that keeps growing, so we keep p95 low and stable under any load.

What you’ll work on

• The rebuild: design new Nest.js services from scratch, with no legacy to patch, and move traffic over without downtime

• Transactions: idempotent, consistent operations that stay safe under heavy concurrency, so no spin is lost or counted twice

• Integrations: third-party APIs from operators and aggregators, built so outside failures never break a spin

• Promo features: real-time tournaments and leaderboards for thousands of players at once

• Analytics: event pipelines into ClickHouse

• Performance: keep p95 and p99 low as traffic grows by profiling Node, tuning Postgres and Redis, and planning capacity on Kubernetes

• On-call: you own what you build, so it’s only fair to take part in our shared on-call rotation

What we’re looking for

• 5+ years of production Node.js and TypeScript, with solid hands-on Nest.js experience

• Experience designing services from scratch with clean, maintainable architecture

• Experience with systems where correctness matters (payments, wallets, ledgers): transactions, locking, idempotency

• Deep Postgres knowledge: indexes, query plans, isolation levels, autovacuum tuning, live migrations

• Redis in production beyond caching (leaderboards, rate limiting, distributed locks)

• Confidence running and debugging services on Kubernetes

It’s a plus if you’ve

• Migrated a live system to a new architecture

• Built GraphQL APIs

• Worked with ClickHouse or another columnar database

• Built event-driven systems with Kafka, NATS or similar

• Set up observability with OpenTelemetry, plus Grafana dashboards and alerts

How we work with AI

We’re AI-first: AI is part of everything we do, from design to code review. A premium Claude subscription is on us, and we keep going deeper. What doesn’t change is ownership: AI writes the code, but people stand behind it.

What we offer

• Competitive salary in USD

• 20 days of paid vacation, 15 sick days, and your birthday off

• Remote work or our office in Barcelona

• 9:00–18:00 or 10:00–19:00 CET, your choice

• Freedom to make architecture decisions, with real ownership of the results

• Zero bureaucracy and direct access to the CTO

• Summer and winter gatherings that bring the whole team together from all over Europe

How we hire

• 30-minute screening call with our recruiter

• 60-minute technical interview on real backend problems, no algorithm puzzles

• 30-minute final interview with the CTO

Feedback at every stage, whatever the outcome.

To apply: send your CV plus a few lines about a system you built where correctness or scale really mattered.