Founding Software Engineer Python - Start-up

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

Benefits offered by this job

Equity

Hybrid work model

Job summary

Client Server Ltd. is seeking a Founding Software Engineer (Python) in London. You will shape the technology and product in an early-stage AI start-up, taking ownership from architecture to deployment on Azure.

The role emphasizes building scalable cloud-native apps, working with Python and TypeScript, and collaborating closely with founders in a flexible, hybrid environment across London and Cambridge, with travel/expenses covered where needed.

Qualifications

• Proven ability to design and build software from scratch.
• Strong Python development skills and experience with web technologies.
• Experience with RESTful APIs and modern frontend frameworks.
• Comfort with AI/LLM technologies and entrepreneurial mindset.

Responsibilities

• Own the design and development of scalable, cloud-native applications across the full SDLC.
• Lead architecture discussions and establish engineering practices for growth.
• Collaborate with founders to influence technical direction and product decisions.
• Work with Python and TypeScript across backend and frontend, including CI/CD and deployment on Azure.

Skills

Python

RESTful APIs

TypeScript

React

HTML5

CSS3

LLMs

Entrepreneurial spirit

Communication

Ownership

Education

BSc in Computer Science or related

2.1 classification (top-tier university)

MSc/PhD (advantage)

Tools

Azure

FastAPI

CI/CD

Job description

Founding Software Engineer Python - Start-up

London, Greater London | £90k - £115k per year

Founding Software Engineer (Python) to £115k

Are you an ambitious full stack Software Engineer who thrives in early-stage environments where you can shape both the technology and the product?

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 Founding Software Engineer, 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