Senior Test Automation Engineer (Python, API, Linux Billing / Rating Systems) UK Remote / Hybrid PermanentWe are recruiting a Senior Test Automation Engineer to join an engineering team building large-scale backend platforms used for billing, rating, and high-volume transaction processing across telecoms and financial-grade systems.This is a backend-focused automation role centred on Python, APIs, and Linux environments. It is not a UI automation role and not a manual QA position.Responsibilities Design, build, and maintain Python-based automation frameworks for backend services Develop and execute automated tests for APIs and service integrations Create coverage for regression, negative, and backward-compatibility scenarios Analyse requirements and define test strategies and test plans for complex backend systems Investigate failures using logs, metrics, and debugging tools in Linux environments Work closely with engineers to identify root causes and improve testability and reliability Support testing of systems deployed in cloud and distributed environments Essential Experience Strong, hands-on experience in Python test automation Proven background testing backend services and APIs Confident working in Linux environments (CLI, logs, troubleshooting) Experience testing billing, rating, charging, payments, or financial transaction systems Solid understanding of authentication and authorisation (OAuth2, JWT, API keys, etc.) Experience with CI/CD pipelines, version control,