Senior Python Developer

Startup Environment, High Ownership, Demanding ClientsJoin 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 solutionsTake full ownership of complex features - from concept and architecture through implementation, testing, and automated deploymentDesign system architecture, APIs, and data models for high-load, data-intensive systemsDeliver core and business-critical components of projectsWork in a dynamic, startup-style environment with changing priorities, tight deadlines, and real product pressureProactively identify risks, bottlenecks, and technical debt, and drive improvementsEnsure high code quality, performance, and reliabilitySupport and mentor other developers, helping raise engineering standards across teamsMust have:5+ years of commercial software development experience, including strong professional experience in PythonExcellent 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 deploymentsProven ability to build efficient, low-latency, scalable systemsConfidence working with tight deadlines, pressure, and frequently evolving requirementsVery good written and spoken EnglishStrong communication skills and a proactive, ownership-oriented mindsetExperience we'd appreciate, too:Experience in system architecture and technical leadershipAsynchronous programming and high-concurrency systemsMessaging systems and distributed architecturesDDD and event-driven designCloud and DevOps experience (AWS / Azure)Mentoring and influencing technical direction of projectsNice to have:Community involvement (meetups, open source, speaking)Writing technical articles or internal knowledge-sharingA list of benefits is long so we will mention only about the crucial ones:Challenging projects with real business impactWork in a startup-like environment: fast decisions, autonomy, responsibility100% remote or office in Poland (Wrocław / Zielona Góra)Sport subscriptionPrivate healthcare