Position Summary: We are looking for a talented Senior Python Engineer to join our Platform & Developer Experience team. This is a fully remote role, and we welcome applications from anywhere in Europe. As part of our Build squad, you will play a critical role in shaping the foundations of developer experience, scalability, and performance of the Crystal platform. More details: crystalintelligence.com Duties and responsibilities: Performance improvements, database query optimisation, and scalability enhancements; Monitoring and observability configuration and best practices; Managing and developing internal libraries; Development pipeline improvements, like code coverage tooling integration, in close collaboration with the DevOps team; Maintaining code to high-quality standards; End-to-end feature design and implementation; Coding, debugging, testing and delivering features and improvements in a continuous manner; Providing code reviews, assistance and constructive feedback to other team members; Refactoring code as necessary. Required: 8+ years of commercial experience developing Python backend services and APIs for the web; Solid software architecture skills; Experience with distributed systems; Strong knowledge of SQL/NoSQL databases and data architecture, including PostgreSQL; Experience with the Flask framework; Experience in performance optimisation (database query optimisation, caching); Understanding of integration processes with external services; Product-oriented mindset; Proficiency in English. Would be a plus: Experience with ClickHouse; Experience with systems operating on large data volumes; Experience designing AI-enabled developer environments; Experience writing raw SQL queries; Experience designing and leading major reworks of complex distributed systems; Experience with Rust; Passion for Bitcoin and blockchain technologies. No previous knowledge of Blockchain technology required. Tech stack: Redis, RabbitMQ, PostgreSQL, ClickHouse; Kubernetes, AWS S3; Python 3.14, Flask, Granian; Datadog, Grafana. You’ll get: AI tool of your choice: Cursor or Claude Code.