Principal Software Engineer

Build the technical foundation of a future unicorn.

Thanks is building the only monetisation platform where advertisers, publishers, and consumers all win. We're a product led organisation, with exciting product-market fit.

Now we’re looking for a Principal Engineer to help define the next chapter of our product engineering organisation - technically, culturally, and strategically.

This is a foundational technical leadership role. You’ll be the most senior engineer in the business, partnering closely with our Head of Product and founders to bring an ambitious vision and roadmap to life, setting the technical bar, and helping us scale both our platform and our team - while remaining meaningfully hands-on.

Why this role exists

Thanks has reached an inflection point.

We have a strong core product in market, new products in active development, and ambitious plans to scale globally. What we now need is exceptional technical leadership - someone who has seen what “great” looks like in start-up and scale-up environments, and can help us build towards it deliberately.

This hire will:

• take ownership of our technical direction,
• uplift a capable but evolving senior engineering team,
• increase velocity without sacrificing long-term quality,
• and help us build the foundations of a world-class engineering organisation.

If we get this hire right, everything accelerates.

The role

As Principal Engineer, you will operate as the de facto Head of Engineering from a technical perspective, without the bureaucracy. This is not a people management role - however, there is a clear pathway to formal leadership if that’s something you want over time.

You’ll work as a true peer to our Head of Product, challenging trade-offs, shaping strategy, and ensuring that technical decisions support both near-term execution and long-term ambition.

You will still write production code - not as your only job, but because the best technical leaders stay close to the work.

What you’ll do

• Set technical direction: Own architecture and system design decisions across the platform, with a focus on speed-to-learning. You will exercise the judgment to move fast on “Two-Way Door” decisions - prioritising modularity and refactorability - while applying deep architectural rigour and planning to the rare “One-Way Door” decisions that underpin our long-term scalability.
• Lead complex, ambiguous initiatives: Break down hard problems, design solutions, and take them from idea to production in a fast-moving environment.
• Raise the technical bar: Set contextual quality standards, system design, testing, performance, and developer experience - and lead by example.
• Be hands-on where it matters most: Design and ship meaningful production code, particularly in high-leverage or high-risk areas of the system.
• Partner deeply with Product and founders: Shape roadmaps, challenge assumptions, and help the business make smart technical trade-offs as we scale.
• Develop engineers and culture: Mentor senior engineers, influence technical standards, and help build a high-trust, high-performance engineering culture.
• Prepare us for scale: Improve observability, reliability, and operational practices as our traffic, revenue, and team grow.