Senior Python Backend Engineer

We are looking for a highly skilled Senior Backend Engineer to join a specialized team building a core evaluation platform for a German-based client.
This system is a critical component of the AI lifecycle, allowing for the comprehensive testing of AI agents through simulated scenarios and real-time performance tracking.
If you are passionate about the intersection of high-performance backend engineering and the rapidly evolving world of AI, this is the project for any developer looking for a long-term challenge.

As a Senior Engineer, you will take full responsibility for developing and scaling backend services. You will work alongside technical leaders and an internal development team to ensure that microservices are high-performance, low-latency, and reliable. This role requires a proactive approach to system design and the ability to handle the "end-to-end" lifecycle of a feature, from initial requirements analysis to production deployment.

Details

• Rate: 140 – 170 PLN/h net + VAT (B2B).

• Duration: Contract through the end of 2026 (strong extension potential).

• Location: 100% Remote

• Collaboration: Part of a dedicated squad of 4–5 engineers.

• On-site Opportunities: Optional "team weeks" in Berlin (roughly twice a quarter for 3–5 days). These visits are not mandatory but are encouraged for team integration.

Responsibilities

• Python Expertise: At least 3 years of experience with modern Python (3.10+), including deep knowledge of asyncio and asynchronous programming.

• Backend Track Record: 7+ years of professional experience building production-grade backend services.

• System Design: Proven ability to design and implement REST APIs and scalable distributed systems.

• Event-Driven Knowledge: Experience with task queues, message brokers, and designing systems resistant to heavy loads.

• Data Management: Production experience with NoSQL (specifically MongoDB), including schema design and query optimization.

• Ownership: A strong sense of responsibility for the code you deliver and the ability to communicate technical risks clearly in English.

Requirements

• Frameworks: FastAPI, Uvicorn, Pydantic.

• Infrastructure: MongoDB (Motor), Redis, Kafka/Azure Event Hubs.

• Cloud & DevOps: Kubernetes, Docker, GitHub Actions, ArgoCD.

• Observability: OpenTelemetry, Datadog, structured logging.

• AI Integration: Working with OpenAI SDKs and managing token usage/costs.