Senior Backend Engineer (Contract) | C# / Kotlin / Java / Go | London Hybrid | £550/£600 per day | Contract at Owen Thomas | B Corp™, London Area, £550/£600 per day

Senior Backend Engineer (Contract) | NodeJS / C# / Kotlin / Java / Go | London Hybrid | £550/£600 per day | Contract

They're looking for Senior Backend Engineers who can do more than simply pick up tickets.

They want people who are technically strong, proactive and comfortable taking ownership of projects, working collaboratively with the wider engineering team and delivering reliable, high-quality systems.

This is an opportunity to join a busy engineering environment where you'll be working on meaningful product integrations, solving complex technical challenges and helping deliver some of the business's highest-priority projects.

What You'll Be Doing

• Building and delivering backend integrations across a range of product initiatives.

• Designing and building reliable, scalable backend systems.

• Working across authentication and identity-related functionality.

• Taking ownership of projects, from understanding requirements through to delivery.

• Collaborating closely with other engineers and stakeholders to drive projects forward.

• Contributing to technical decisions and maintaining high engineering standards.

Core Skills & Experience

Essential

• Strong commercial backend engineering experience at Senior level.

• 4–5+ years of professional software engineering experience.

• Strong experience with at least one strongly typed backend language, such as C#, Kotlin, Java or Go.

• Experience building and maintaining reliable, production-grade systems.

• Ability to take ownership of technical projects and deliver with minimal hand-holding.

• Strong communication and collaboration skills.

• A proactive approach to problem-solving and engineering quality.

Strongly Preferred

• Experience working on integrations with third-party platforms or APIs.

• Experience with authentication, authorisation and identity systems.

• Experience working on billing, payments or invoicing functionality.

• Experience working across complex product integration projects.

• Previous experience in product-led or fast-paced engineering environments.

Nice to Have

• Experience with multiple strongly typed programming languages.

• Previous experience within start-up or scale-up environments.

Contract Details

• Multiple contractor positions available

• London-based hybrid working, ideally 2–3 days per week in the office.

• Day rate: £550/£600

• IR35 status: Outside

If you're an experienced Backend Engineer with strong experience in C#, Kotlin, Java, Go or another strongly typed language, enjoy building reliable systems and like taking ownership of projects rather than simply working through tickets, this is an excellent opportunity to get involved in a busy engineering roadmap.

Apply here, and we'll be in touch if it looks like a good fit. :)