Senior Backend Engineer (FastAPI)
⚲ Warszawa
8 000 - 12 500 USD netto (B2B)
Wymagania
- Redis
- RabbitMQ
- AI Foundry
- RAG
- fastapi
- ARQ
- SQL
- Celery
- Python
- NoSQL
Opis stanowiska
About us
comm1t is a specialist IT recruitment agency delivering top engineers across Poland and Europe 🇪🇺. We combine experienced recruiters with autonomous AI agents and an obsessive focus on quality — sourcing 24/7 across LinkedIn, GitHub, and beyond to reach engineers who aren't actively job hunting but are open to the right move.
We don't flood you with CVs. We get to know each candidate's skills, values, and goals, then send only the best-matched people — and we stay close through onboarding and the first months to make sure the placement lasts.
About the role
You'll lead the backend that drives the AI features — the APIs, the data pipelines, and the orchestration that connects the product to the language models doing the actual work. In practice that's querying across large document sets, getting trustworthy answers out of LLMs and their tool calls, pushing results to the UI as they stream, and grinding through lengthy background jobs without the whole thing toppling over.
Forget CRUD. The real difficulty is making AI systems fast and reliable on confidential data, at production scale. The architecture choices land on you early, and you'll be the one living with them.
What you'll do
• Architect and ship the APIs and services that everything else depends on
• Own the AI plumbing end to end: retrieval, orchestration, tool-calling, streaming, and the evals that tell you whether the results are worth anything
• Make async and distributed workloads rock-solid — document ingestion, embeddings, and long jobs running on Redis
• Wire up integrations with what clients already use (email, document stores) and harden them for real-world traffic
• Put data security and isolation front and center, because clients are handing over material they can't afford to leak
Who you are
• Seven years or more delivering production backends — though how deep you go matters more to us than the figure itself
• You think in failure modes, not just the happy path
• You've shipped genuine LLM systems (RAG, tool-calling, agents), or you can't wait to — and you've got a feel for where they fall apart
• You lean on AI coding tools (Claude Code, Cursor, Copilot) and get real value from them: more speed, yes, but you grasp and back every line — code you'd reject in someone else's review is code you won't merge in your own
• A startup that keeps changing course doesn't faze you — plans get set, then torn up and redrawn
Tech stack experience
• Python: 6+ years
• FastAPI: 3+ years
• PostgreSQL / SQL
• Redis: 2+ years
Nice to have
• RAG or vector search experience
• LangChain or LlamaIndex
comm1t is a specialist IT recruitment agency delivering top engineers across Poland and Europe 🇪🇺. We combine experienced recruiters with autonomous AI agents and an obsessive focus on quality — sourcing 24/7 across LinkedIn, GitHub, and beyond to reach engineers who aren't actively job hunting but are open to the right move.
We don't flood you with CVs. We get to know each candidate's skills, values, and goals, then send only the best-matched people — and we stay close through onboarding and the first months to make sure the placement lasts.
About the role
You'll lead the backend that drives the AI features — the APIs, the data pipelines, and the orchestration that connects the product to the language models doing the actual work. In practice that's querying across large document sets, getting trustworthy answers out of LLMs and their tool calls, pushing results to the UI as they stream, and grinding through lengthy background jobs without the whole thing toppling over.
Forget CRUD. The real difficulty is making AI systems fast and reliable on confidential data, at production scale. The architecture choices land on you early, and you'll be the one living with them.
What you'll do
• Architect and ship the APIs and services that everything else depends on
• Own the AI plumbing end to end: retrieval, orchestration, tool-calling, streaming, and the evals that tell you whether the results are worth anything
• Make async and distributed workloads rock-solid — document ingestion, embeddings, and long jobs running on Redis
• Wire up integrations with what clients already use (email, document stores) and harden them for real-world traffic
• Put data security and isolation front and center, because clients are handing over material they can't afford to leak
Who you are
• Seven years or more delivering production backends — though how deep you go matters more to us than the figure itself
• You think in failure modes, not just the happy path
• You've shipped genuine LLM systems (RAG, tool-calling, agents), or you can't wait to — and you've got a feel for where they fall apart
• You lean on AI coding tools (Claude Code, Cursor, Copilot) and get real value from them: more speed, yes, but you grasp and back every line — code you'd reject in someone else's review is code you won't merge in your own
• A startup that keeps changing course doesn't faze you — plans get set, then torn up and redrawn
Tech stack experience
• Python: 6+ years
• FastAPI: 3+ years
• PostgreSQL / SQL
• Redis: 2+ years
Nice to have
• RAG or vector search experience
• LangChain or LlamaIndex
🔍 Dekoder Ogłoszenia
🟡
Forget CRUD.
Oznacza to, że projekt wykracza poza podstawowe operacje na bazie danych i wymaga bardziej zaawansowanych rozwiązań architektonicznych.
🔴
The architecture choices land on you early, and you'll be the one living with them.
Oczekuje się od Ciebie samodzielnego podejmowania kluczowych decyzji architektonicznych, za które będziesz ponosić długoterminową odpowiedzialność.
🟡
Own the AI plumbing end to end: retrieval, orchestration, tool-calling, streaming, and the evals that tell you whether the results are worth anything
Obejmuje to pełną odpowiedzialność za wszystkie aspekty techniczne związane z integracją i działaniem modeli AI, w tym za ich ocenę jakościową.
🟡
Make async and distributed workloads rock-solid
Wymaga to zapewnienia stabilności i niezawodności systemów działających w sposób asynchroniczny i rozproszony, co może być złożone.