Founding Engineer

SR2 | Socially Responsible Recruitment | Certified B Corporation™; Greater London; Hybrid; GBP 90,000 - 115,000; Full time

Benefits offered by this job

Equity

Job summary

SR2 | Socially Responsible Recruitment is partnering with an early-stage AI company in London seeking a Founding Engineer to join a small, mission-driven team building safety-critical AI products. You'll own backend development in Python with FastAPI, design APIs over PostgreSQL, and influence architecture and engineering culture as the product scales.

Hybrid London, equity on offer, and a chance to ship real solutions with paying customers.

Qualifications

• 1–5 years of commercial engineering experience.
• Strong Python and modern web app framework experience.
• Experience building AI/LLM features in production.
• Thrives in an early-stage, high-caliber engineering team.
• Product mindset and willingness to own across the stack.

Responsibilities

• Build production-grade agentic AI workflows and LLM-powered features.
• Own backend development with Python and FastAPI.
• Design APIs and data architecture using PostgreSQL.
• Shape architecture and engineering standards as the company grows.
• Collaborate with users to translate problems into simple products.

Skills

Python

FastAPI

Django/Flask

LLM/AI production

Architecture fundamentals

Product mindset

React/TypeScript exposure

Ownership

Tools

PostgreSQL

Azure

Job description

Salary: Up to £115,000 + meaningful equity

Location: London, hybrid

This is for those who are serious about mission & impact.

I'm working with an early-stage AI company building technology for safety-critical, highly regulated environments.

The product is already live, paid for and being used daily, so this isn't an AI idea waiting around for a use case. The next phase is about taking something that's working, scaling the platform and expanding into new markets.

The role

You'll join a team of around 10 as a Founding Engineer, working closely with the founders and taking genuine ownership across product and engineering.

You'll be:

• Building production-grade agentic AI workflows and LLM-powered product features
• Owning backend development using Python and FastAPI
• Designing APIs, services and data architecture using PostgreSQL
• Working across architecture, infrastructure, CI/CD and Azure
• Contributing across React/TypeScript where needed
• Working directly with users to understand messy real-world problems and turn them into simple products
• Influencing technical architecture, product direction and engineering standards as the company grows

There won't always be a perfectly written ticket waiting for you. A big part of the job is working out what should actually be built, then making it happen.

What they're looking for

The backend bar is important. You'll need strong commercial Python experience and ideally experience building modern web applications with FastAPI, Django, Flask or similar.

Beyond that, they're looking for:

• Roughly 1–5 years of commercial engineering experience
• Strong software engineering and architectural fundamentals
• Experience building LLM/AI functionality in production, rather than purely personal experimentation
• Evidence you've thrived in an early-stage environment or another high-calibre engineering team
• A product mindset and willingness to work across the stack
• High ownership, curiosity and comfort operating without everything being predefined

Experience with clean architecture, domain-driven design and event-driven systems would be particularly useful.

Why this one?

Tech4Good with teeth. The software you build will directly affect how teams operate within safety-critical environments.

You'll get founding-level ownership without being pre-product, working alongside an ambitious technical team with paying customers and real-world validation already behind them.

There's also significant scope to shape the architecture, product and engineering culture while the company is still small enough for your decisions to matter.

If you're an ambitious Python Engineer who wants to build real AI products, solve difficult problems and have considerably more influence than your job title normally allows, I'd love to speak.