Senior Backend Engineer

Senior Backend Engineer £100,000 - £140,000 + equity Office based in London We've partnered with a profitable, fast-growing (10x last year) AI company building LLM-powered tools that are already used by some of the world's largest private equity and consulting firms. The team is 40+ across London & New York and this is a key backend hire for the London office. You'll own backend systems end-to-end: architecting and scaling infrastructure for high-throughput LLM interactions, vector search and multi-agent orchestration, building retrieval pipelines, caching layers and async task queues, and stitching together model providers, data stores and internal APIs into clean, performant systems. There's real scope to shape engineering culture and infrastructure decisions early. You might be a fit if you: Ship fast and have owned technical projects from architecture through productionWrite strong production TypeScript (Python also welcome)Know your way around PostgreSQL and care about data modelling, reliability and system designEnjoy turning messy business problems into clean systems and automationThrive in lean, fast-moving startups and can work directly with non-technical stakeholders Bonus: billing / payments or usage-based pricing, internal dev tooling, event-driven systems, or retrieval / embeddings / prompt orchestration. On offer: competitive salary plus equity, private health insurance, gym membership, lunch in-office, multiple all-expenses paid offsites a year, and visa sponsorship. Flat structure, direct access to the founders, five days a week in a Farringdon office. Apply here or message me directly for a confidential chat.