Senior Backend Engineer

To be honest this isn’t another backend role where you’re maintaining an existing platform, adding features to an internal CRM or picking up tickets from a backlog.

We’re partnering with a well-funded AI company building a completely new product from 0*1, and they’re looking for the kind of engineer who gets excited by a blank page.

You’ll be working directly with the CTO and founders, making real architectural decisions and taking ideas all the way from “could we build this?” * production * real users. The interesting part is the engineering.

You’re dealing with AI agents, LLM orchestration, APIs, data pipelines, asynchronous processing, third-party integrations and the reliability problems that come with putting AI into production. There’s no perfectly defined technical specification waiting for you. You’ll have to figure it out.

If you’re a strong Software Engineer with Python/backend fundamentals, a strong CS foundation and you’ve already built products that made it into production this is the sort of role I want you to see.

What you’ll actually be doing

• Architect and build the backend from the ground up you’ll have a genuine say in how the system is designed
• Take ideas from 0*1, through architecture, implementation, deployment and iteration
• Build high-performance APIs, background workers, data pipelines and third-party integrations
• Design and ship AI agent workflows, including LLM orchestration, tool calling and retrieval
• Solve problems around latency, reliability, observability, cost and model performance
• Make the difficult calls around architecture, infrastructure and technical trade-offs
• Work directly with the CTO and founders - no six layers between you and the decision
• Ship to real users, learn from what breaks, and improve it

• Excellent software engineering fundamentals CS fundamentals actually matter here
• Strong production experience with Python
• Strong backend/API engineering experience
• Experience building and shipping 0*1 products or significant greenfield systems
• Strong understanding of distributed systems, databases, concurrency and asynchronous processing
• Hands-on experience with LLMs, AI agents, RAG, embeddings or model-driven applications
• Someone who can look at an ambiguous problem and work out the architecture rather than waiting for someone else to define it
• A track record of shipping GitHub, products, side projects, startups, whatever proves you build

You’ll stand out if you’ve worked with

• FastAPI / Django
• PostgreSQL
• AWS
• Redis / Celery / Kafka
• Vector databases
• Agent orchestration / tool calling
• RAG / retrieval systems
• LLM evaluation and observability
• AI-native products
• High-growth startups
• Strong open-source projects

Top university / Computer Science background is highly valued, particularly from places such as Imperial, Cambridge, Oxford, UCL, Edinburgh or Warwick but I’m much more interested in what you’ve actually built than a university name on a CV.