Lead Python Engineer API LLM - Start-up

Client Server; Greater London; Hybrid; GBP 90,000 - 115,000; Full time

Benefits offered by this job

Equity

Hybrid work

Job summary

Client Server is seeking a Lead Python Engineer to own the design and development of scalable, cloud-native applications. You’ll work across the full software lifecycle from architecture to frontend, CI/CD and deployment on Azure, in a hands-on, autonomous role.

Join a fast-growing AI start-up building compliance tech for regulated industries. You’ll influence technical direction, collaborate with founders, and contribute to product decisions with Python, TypeScript and AI capabilities.

Qualifications

• Degree educated, minimum 2.1 at BSc from a top tier university, Computer Science or closely related discipline preferred
• Likely to have studied MSc / PhD
• Experience building production-grade APIs with Python and modern web tech

Responsibilities

• Design and develop scalable, cloud-native applications from architecture to deployment on Azure
• Own the full software development lifecycle across backend and frontend technologies
• Collaborate with founding team to set engineering direction and practices
• Hands-on with Python and TypeScript, leveraging AI tech in product development

Skills

Python

REST APIs

TypeScript

React

HTML5

CSS3

LLMs

AI

Collaboration

Degree required

Education

BSc Computer Science or related

MSc / PhD (preferred)

Tools

FastAPI

Azure

Job description

Lead Python Engineer API LLM - Start-up (PR/100924) London, England

Salary: GBP90000 - GBP115000 per annum + benefits

Lead Python Engineer / Developer (API LLM Python) to £115k

Do you have advanced Python skills combined with tech start-up experience?

You could be joining a fast growing AI start-up as one of its founding engineers, helping to build technology that is transforming compliance and operational efficiency across the NHS and wider regulated industries. With strong backing and ambitious growth plans, you'll have the chance to make a genuine impact while working alongside experienced founders in a highly collaborative environment.

As a Lead Python Engineer and founding team member, you'll take ownership of the design and development of scalable, cloud-native applications, working across the full software development lifecycle, from architecture and backend services through to frontend development, CI/CD and deployment on Azure.

You'll collaborate closely with the founding team to influence technical direction, solve complex engineering challenges and establish the engineering practices that will underpin the company's future growth.

You'll work primarily with Python and TypeScript, leveraging AI technologies to build innovative products that solve real world problems. This is a hands-on role with plenty of autonomy, where you'll have a direct influence on product decisions, architecture and engineering culture.

Location / WFH:

You’ll join the team in London two days a week, with one day a week in Cambridge too (expenses covered) and flexibility to work from home.

About you:

• You enjoy taking ownership and can build software from scratch and iterate quickly
• You have strong technical skills, primarily with Python
• You have experience with RESTful APIs (they use FastAPI); TypeScript, React and other web technologies such as HTML5, CSS3 would be of benefit
• You have experience with LLMs and agentic AI, like to get your hands dirty and have a proactive entrepreneurial spirit
• You’re curious by nature, happy to learn and pick up new things
• You’re keen to work in a start-up environment, comfortable with unstructured environments
• You’re collaborative with great communication skills
• You are degree educated, minimum 2.1 at BSc from a top tier university, Computer Science or closely related discipline preferred, likely to have studied to MSc / PhD

What’s in it for you:

• Salary to £115k
• Equity
• Impactful role with excellent career growth opportunities