Founding Software Engineer Python - Start-Up

Client Server; Greater London, Cambridge; Hybrid; GBP 98,000 - 115,000; Full time

Benefits offered by this job

Equity

Job summary

Client Server is seeking a Founding Software Engineer (Python) in the UK to help shape core technology and product in a fast-growing AI startup. You will own the design and build of cloud-native applications, spanning backend services, frontend work, CI/CD pipelines, and Azure deployment.

You will work with Python and TypeScript, leveraging AI tools to deliver scalable solutions. London/Cambridge-based with hybrid working and equity sharing as part of the package.

Qualifications

• Ownership of design and development for cloud-native applications.
• Experience with Python as primary language.
• Experience building RESTful APIs (FastAPI).
• Proficiency with TypeScript/React and web tech (HTML5/CSS3).
• Experience with LLMs and agentic AI.
• Degree educated, 2.1+ in CS or related field; MSc/PhD preferred.

Responsibilities

• Own the design and development of scalable cloud-native apps.
• Contribute across the full SDLC from architecture to deployment.
• Work with founding team to set technical direction and practices.
• Build backend services and frontend interfaces, CI/CD, and Azure deployment.

Skills

Python

REST APIs (FastAPI)

TypeScript

React

HTML5

CSS3

LLMs / Agentic AI

Ownership / Startup mindset

Azure

CI/CD

Git

Education

BSc in Computer Science or related

MSc/PhD preferred

Tools

FastAPI

Azure

Git

CI/CD

Job description

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