Senior Backend Engineer - Python

Senior Backend Engineer - Python London preferred, open to remote Up to £135k + annual bonus Profitable, bootstrapped SaaS scale-up I've partnered with an established, highly profitable SaaS business that is going through an exciting period of growth. Their platform is used by leading financial and professional-services organisations to make better decisions from complex data. They're looking for a Senior Backend Engineer to join their engineering team and play a key role in scaling their platform and developing a new generation of data and AI-powered capabilities. The Role You'll take ownership across the Python backend, working closely with product, data and frontend engineers to build reliable, scalable systems. You'll be involved in: Designing and developing high-quality APIs and backend servicesWorking with large-scale datasets and optimising complex SQL queriesBuilding infrastructure to support new AI-powered functionalityImproving the scalability, reliability and performance of the platformWorking closely with data engineering and frontend teams to deliver end-to-end featuresHelping shape technical decisions as the engineering team continues to grow Who You Are Strong commercial experience with PythonExperience building production APIs using FastAPI or another modern async frameworkStrong SQL and relational database knowledgeComfortable working with large datasets and performance optimisationA track record of taking ownership of projects from idea through to productionSomeone who enjoys working autonomously and solving ambiguous problemsComfortable working in a fast-moving product environment Nice to have: experience with analytical databases such as ClickHouse, Redshift or Snowflake, data-intensive products, TypeScript, cloud infrastructure or mentoring junior engineers. The Environment This is a high-autonomy engineering environment where you'll have genuine influence over how things are built. They're looking for engineers who enjoy solving real problems pragmatically rather than over-engineering solutions. You'll have the opportunity to work across the stack, influence architecture and help shape the next stage of the company's technical growth.