Senior Backend Engineer | London | AI x 0→1 Product | Python | Competitive Salary + Equity
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
What I'm looking for
- 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.
Why this one is different
You won't be joining a huge engineering organization and owning 3% of a service nobody understands. You'll be one of the engineers actually building the thing. You'll have direct access to the people making the decisions, meaningful equity, serious technical ownership and the opportunity to put your fingerprints on the architecture before it becomes difficult to change.
If you're the type of engineer who sees 0→1, greenfield, AI agents and “figure it out” and thinks that's exactly what I want to be doing! I'd like to hear from you
Apply with your CV.
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