About

Jonas Mattes

A decade of shipping software — now in service of early-stage founders.

I'm a senior full-stack TypeScript engineer based in Cambridge. Over the last ten years I've written software inside some of the most demanding engineering organisations in the world; today I bring that experience to startups and scale-ups who need a senior pair of hands to get a product built and shipped.

I take on one or two engagements at a time so each gets the focus it needs. The work spans the whole arc — shaping the idea, building the product end-to-end, and integrating AI features that actually pull their weight rather than bolting an API call onto the side.

Experience

  1. Now

    Freelance AI-product engineer · Independent · Cambridge

    I partner with early-stage startups, university spinouts, and scaling teams to take product ideas and stalled prototypes to production — design, build, and launch, with AI features built in where they earn their place. Most recently I rebuilt a German edtech platform from the ground up and took it 0→1, from prototype to pilot schools.

  2. Previously

    Software engineer · Google

    Built and shipped production software at Google scale, working across a large engineering organisation on systems used by millions. It set the bar for how I think about reliability, code quality, and shipping software that other engineers can maintain.

  3. Before that

    Software engineer & consultant · Zühlke

    Delivered software products for enterprise clients as part of a consulting team — including work for SBB, the Swiss national railway. Consulting taught me to drop into an unfamiliar domain, earn trust quickly, and ship something real against a real deadline.

  4. Early career

    Working student · BMW · Audi

    Cut my teeth as a working-student engineer at two of Germany's automotive giants while studying — my first taste of writing software inside large, demanding engineering organisations.

Toolkit

I work primarily in TypeScript across the stack, with a bias towards type-safety end-to-end so the codebase scales with the product and hands off cleanly to whoever comes next.

  • TypeScript
  • Next.js
  • React
  • Angular
  • tRPC / oRPC
  • Hono
  • Postgres
  • Drizzle
  • Supabase

Want a senior engineer on your product?

I take on 1–2 projects at a time. Let's talk about yours.

Get in touch →