Senior Python Developer

Startup Environment, High Ownership, Demanding Clients Join our startup-like environment filled with new ideas, rapid change, and a strong focus on priorities and delivery. We are looking for a Senior Python Developer - someone experienced, open-minded, and ready to take real ownership of both product and technical direction. You will work closely with demanding clients, solve complex engineering problems, and help shape ambitious, high-performance systems. This role is for engineers who enjoy responsibility, fast feedback loops, architectural challenges, and working under pressure. Your primary responsibilities beyond the will to change the world: • Act as a technical partner for clients: analyze business needs, challenge requirements, and propose effective, scalable solutions • Take full ownership of complex features - from concept and architecture through implementation, testing, and automated deployment • Design system architecture, APIs, and data models for high-load, data-intensive systems • Deliver core and business-critical components of projects • Work in a dynamic, startup-style environment with changing priorities, tight deadlines, and real product pressure • Proactively identify risks, bottlenecks, and technical debt, and drive improvements • Ensure high code quality, performance, and reliability • Support and mentor other developers, helping raise engineering standards across teams Must have: • 5+ years of commercial software development experience, including strong professional experience in Python • Excellent knowledge of Python 3.11+ (typing, dataclasses, modern best practices) • Production experience with modern Python frameworks ( async FastAPI preferred, Falcon welcome, Async SQLAlchemy 2.0) • Strong expertise in API design (REST, GraphQL) • Solid understanding of databases and data-driven systems (relational, document, search, key-value stores) • Advanced knowledge of software engineering principles (OOP, SOLID, YAGNI, TDD) • Extensive experience with unit testing (pytest), CI/CD pipelines, Docker, and deployments • Proven ability to build efficient, low-latency, scalable systems • Confidence working with tight deadlines, pressure, and frequently evolving requirements • Very good written and spoken English • Strong communication skills and a proactive, ownership-oriented mindset Experience we'd appreciate, too: • Experience in system architecture and technical leadership • Asynchronous programming and high-concurrency systems • Messaging systems and distributed architectures • DDD and event-driven design • Cloud and DevOps experience (AWS / Azure) • Mentoring and influencing technical direction of projects Nice to have: • Community involvement (meetups, open source, speaking) • Writing technical articles or internal knowledge-sharing A list of benefits is long so we will mention only about the crucial ones: • Challenging projects with real business impact • Work in a startup-like environment: fast decisions, autonomy, responsibility • 100% remote or office in Poland (Wrocław / Zielona Góra) • Sport subscription • Private healthcare