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.