Senior Python Software Engineer

Location: [Poland] We Are: RTB House is a global company that provides state-of-the-art marketing technologies for top brands and agencies worldwide. Its proprietary ad-buying engine is the first in the world to be powered entirely by Deep Learning algorithms, enabling advertisers to generate outstanding results and reach their goals at every stage of the funnel. We are looking for a Senior Python Software Engineer to join our internal team at RTB House. In this role, you will own complex technical challenges, design and scale backend systems, and deliver solutions that directly support our core business in real-time bidding. This position is ideal for engineers who thrive on problem-solving, system design, and building reliable software that has immediate impact. At the same time, we combine local expertise with our broader company vision, giving you both autonomy and the opportunity to contribute to a truly global product. You Will: Design, develop, and maintain internal web applications responsible for ad campaigns management, e.g. configuration, monitoring, automation Drive the design and implementation of jobs and processes integrating internal services at scale Take ownership of complex technical topics end-to-end: explore new domains, clarify requirements, decompose problems, and deliver robust solutions Identify and eliminate bottlenecks, implement performance optimizations to maximize efficiency, scalability, and reliability Write and maintain unit/integration tests to ensure code quality and long-term stability Shape and evolve internal Python libraries and frameworks used across teams Collaborate with cross-functional teams, providing clear technical guidance and translating complex concepts into simple explanations Desired Experience: Proven experience in backend development with Python, writing reliable, maintainable, and testable code Strong knowledge of SQL, relational/analytical databases, indexing, query optimization, and performance tuning (PostgreSQL, BigQuery) Experience in asynchronous programming and building distributed or event-driven systems Practical experience in designing APIs (REST, GraphQL) and understanding of HTTP/web internals Solid understanding of system design fundamentals: scalability, availability vs. consistency trade-offs, caching, data modeling Ability to independently lead technical initiatives: from exploring requirements, evaluating alternatives, making design trade-offs, to implementation Experience in writing high-quality, well-tested, maintainable code Excellent problem-solving skills: structured thinking, decomposition of complex issues, prioritization Strong communication skills: ability to explain technical matters clearly to both engineers and non-technical stakeholders Fluency in English Comfort working in a fast-paced environment, balancing multiple priorities effectively Selected Technologies: Backend: Python, FastAPI Databases: PostgreSQL, BigQuery GraphQL: Ariadne Messaging: Google Pub/Sub Data Handling Validation: Pydantic, dataclasses Testing: Pytest Monitoring: Sentry, Prometheus, Grafana CI/CD: GitHub Actions Cloud: GCP, Kubernetes We Offer: Being part of a small team with a high degree of autonomy and decision-making Attractive compensation Access to the latest technology in the developed solution Opportunity to build and improve our own products, where long-term quality and reliability truly matter Participation in one of the most interesting projects of the online industry in Poland and one of the fastest growing technology companies in Europ Apply now! You don't need to tick every box to apply. If you are passionate about digital marketing, send us your CV, and we'll review it. ... (truncated, view full listing at source)