Senior Python Developer at Flipper

Hi! This is the Flipper Devices team. We are the creators of Flipper Zero — a portable device for tech enthusiasts and engineers. It’s a gadget with an awesome community that brings together millions of people around the world. We are now starting development of a new software product in the telecom industry and are looking for the first Backend Developer to join the team and help build its Python backend from the ground up. What you will be working on - Develop the product’s backend platform, including accounts, authentication, billing, payments, and internal user state management. - Work with subscription-based and one-time purchase flows, supporting payment scenarios and related user journeys. - Integrate external services and APIs, including payment systems, KYC providers, and telecom infrastructure. - Build and improve eSIM provisioning logic and related subscriber lifecycle processes. - Contribute to the development of a policy engine for managing speed modes, balances, access rules, and other service parameters. - Work with usage data, metrics, and real-time events, including delivering this data to the user dashboard. - Develop background jobs and automations, including email notifications, critical event handling, and recurring service tasks. - Design and maintain reliable backend processes with a strong focus on security, fault tolerance, and auditability. - Contribute to architecture decisions and help turn complex business logic into clear, reliable services. Requirements - 5+ years of Python backend development in production environments - Strong FastAPI or equivalent async Python framework experience - Stripe integration experience: webhooks, idempotency keys, subscription lifecycle - PostgreSQL: schema design, query optimisation, understanding of ACID transactions and when they matter - Celery in production: task design, beat scheduling, idempotency, failure handling, retry strategies - Redis: sessions, rate limiting, pub/sub, understanding of data structures and expiry - WebSocket backend experience: connection management, reconnection, fan-out to multiple clients - Strong understanding of REST API design, HTTP semantics, and webhook security (signature verification) - Experience with financial or billing systems Nice to have - KYC integration experience (Stripe Identity, Onfido, Jumio, or similar) - Experience building systems with strict audit log requirements (financial, healthcare, or similar regulated domain) What we offer - Choose your work format: office, hybrid, or fully remote from anywhere in the world - You will be provided with all the necessary equipment for a comfortable working environment - Benefits such as VHI, corporate sports, foreign language courses, and therapy sessions - A well-equipped office with all the amenities you might need - A five-day workweek with a flexible start of the working day