Staff Full Stack Engineer

We're looking for one engineer, not a shortlist. This role is for someone who has already built and owned a system at scale, not someone who wants to learn how. If you've spent your career executing someone else's architecture, this isn't the right fit; if you've made the calls and lived with the consequences, keep reading.

About the Project

The product runs real-time, multiplayer-style logic for thousands of users acting within the same few seconds, backed by a transactional data layer that cannot afford to get locking or constraints wrong. It handles live payments, subscriptions and webhook-driven state changes where a bug isn't cosmetic, it's money out the door. LLM features are already shipped to real external users, not sitting in a demo branch.

Responsibilities

• Own the full path from database to browser, including transaction design, locking behavior and performance under concurrent load in PostgreSQL;

• Run Redis in production for caching, pub/sub and distributed locks;

• Build and maintain WebSocket-based real-time state sync for large numbers of concurrently active users;

• Own payment provider integrations end to end, including subscriptions, refunds and retry-safe webhook handling;

• Ship LLM-powered features to production, evaluate their real-world behavior, and iterate based on external user impact;

• Make architecture decisions directly, not relay them from someone else's spec;

• Use LLMs as part of your own development workflow to move faster without cutting corners.

Qualifications

• Strong, structured thinking and problem-solving, with the ability to reason clearly about tradeoffs under pressure;

• Track record of building a system that scaled to hundreds of thousands or millions of users;

• Deep hands-on PostgreSQL experience: transactions, locking, constraint design, performance under load;

• Production experience with Redis for caching, pub/sub and locking;

• Strong command of TypeScript/Node or Python, paired with a React-class front end;

• Proven experience with WebSockets and real-time state synchronization at scale;

• Hands-on experience with a payment provider such as Stripe, covering subscriptions, refunds and retry-safe webhooks;

• At least one shipped LLM feature used by real external users, not an internal prototype or demo;

• Personal ownership of a system where a bug carried real financial or operational consequences;

• History of making architecture decisions rather than executing someone else's;

• Minimum 4 hours of daily overlap with US Eastern time.

Recruitment Process

• Initial screening with Inuits to confirm technical depth and availability;

• Technical assessment set by the hiring team;

• Interview with the CTO;

• Offer and onboarding.

Inuits Sp. z o.o. is registered in the National Register of Employment Agencies (KRAZ) under number 35420.