Senior Software Engineer

Senior Software Engineer | YC-Backed Startup | Founding Team | £90K-£120K + Equity

I'm working with an exciting YC-backed startup in London that's just closed a multi-million pound funding round and is looking for a Senior Software Engineer to join their founding engineering team.

Despite being early-stage, they're already punching well above their weight – with paying customers onboarded and serious traction in their market. This is a rare opportunity to get in at the ground floor of something special.

What you'll be doing:

  • Working directly alongside the founders to build and scale the product
  • Taking real ownership over technical decisions and architecture
  • Shaping the engineering culture and technical direction from day one
  • Building features that directly impact paying customers

The tech:

  • Python
  • TypeScript
  • React/Next.js

What's in it for you:

  • £90,000 - £120,000 base salary + Equity
  • 3 days per week in their London office (hybrid working)
  • Direct impact on product and company direction
  • Work with world-class founders backed by Y Combinator

What they're looking for:

  • Strong commercial experience with Python and TypeScript
  • Experience with React/Next.js or similar modern frontend frameworks
  • Someone who thrives in fast-paced, early-stage environments
  • A builder who wants ownership, not just tickets to complete

If you're a senior engineer looking to step into a founding team role at a startup with genuine momentum, let's talk.

Job Details

Company
HartleyCo
Location
Slough, Berkshire, UK
Hybrid / Remote Options
Employment Type
Full-time
Posted