Senior Backend Engineer

My client, a fast-growing technology company, is looking for a Senior Backend Engineer to join their team. This is a hands-on senior engineering role focused on Python, FastAPI, backend architecture, AI/LLM integration, RAG, data pipelines, distributed systems and building secure, reliable production services.

The Job:

• Design, build and maintain scalable backend APIs and services supporting AI-powered applications.
• Develop AI-focused backend functionality including retrieval, orchestration, tool-calling, response streaming and evaluation workflows.
• Build and maintain data pipelines for document ingestion, processing and embedding generation.
• Develop reliable asynchronous and distributed workloads, including long-running background jobs using Redis.
• Build integrations with external systems such as email platforms, document management systems and other third-party services.
• Design backend architecture with a strong focus on reliability, performance, scalability and fault tolerance.
• Develop systems capable of securely processing and isolating confidential and sensitive customer data.
• Troubleshoot complex production issues and design systems with failure scenarios, resilience and recovery in mind.
• Work closely with product and engineering teams to make architectural decisions and deliver robust backend solutions.
• Take ownership of backend services from design through development, testing, deployment and ongoing optimisation.

Have you:

• 7+ years' experience building and supporting production-grade backend systems, with strong depth in backend engineering.
• 6+ years' hands-on Python development experience, building scalable and production-grade backend systems.
• 3+ years' commercial FastAPI experience, developing high-performance APIs and backend services in production environments.
• Strong experience with PostgreSQL and SQL, including designing and working with relational data.
• 2+ years' experience with Redis, particularly for asynchronous processing, caching or distributed workloads.
• Hands-on experience building LLM-powered applications, with knowledge of RAG, tool-calling and/or AI agents.
• Experience with distributed systems, asynchronous processing, background jobs and building reliable production services.
• Experience with AI coding tools such as Claude Code, Cursor or GitHub Copilot, with the ability to review and take ownership of AI-generated code.
• Experience with RAG/vector search, LangChain or LlamaIndex, and streaming technologies such as SSE or WebSockets is highly desirable.
• Experience integrating with Microsoft Graph, email platforms or document management systems, combined with a strong understanding of data security and isolation.