Senior Back End Developer (.Net)

Senior Back End Engineer (.NET)Location: Fully remote (UK-wide only).

We do have an office in Old Street, London, which you’re welcome to use if you like. We also run company-wide meetups twice a year (previous off-sites include Paris and the Cotswolds).

About Claimit

Claimit is a rapidly growing, seed-stage AI tech startup transforming claims management through intelligent automation. We help businesses manage logistics, loss and damage claims more efficiently by removing manual effort and friction from complex processes.

We’re scaling quickly, solving genuinely hard problems, and building software that has a real impact on customers. We’re looking for senior engineers who enjoy ownership, care about clean systems, and thrive in a fast-moving startup environment.

Role Overview

We’re looking for a Senior Back End Engineer to play a key role in the design, build and evolution of Claimit’s core platform.

You’ll focus primarily on back end systems and APIs, working within our Microsoft stack as we move through .NET 9 and towards .NET 10. This is a senior, hands-on role where you’ll help shape architecture, improve reliability and performance, and raise the bar on engineering standards as we scale.

You’ll work closely with the CTO, product, and other engineers to design robust services that support customer-facing features, AI-driven workflows and analytics-heavy use cases.

Key Responsibilities

• Design, build and maintain scalable, secure and performant back end services using C# and ASP.NET Core.
• Own and evolve APIs, data models and business logic that underpin Claimit’s platform.
• Contribute to architectural decisions as we modernise and scale our systems, including our transition to .NET 9 and beyond.
• Work closely with product and engineering to translate requirements into well-structured, production-ready solutions.
• Improve and maintain CI/CD pipelines, testing strategies and deployment processes in Azure.
• Ensure high standards of code quality through testing, peer review and thoughtful system design.
• Identify and address performance, scalability and security concerns as usage grows.

What We’re Looking For

• Strong commercial experience as a Senior Back End Engineer (or similar), ideally in a start-up or scale-up SaaS environment.
• Deep knowledge of C#, ASP.NET Core, and modern .NET development practices.
• Experience building and maintaining APIs, background services and data-heavy systems.
• Solid experience with SQL databases (e.g. SQL Server, PostgreSQL) and ORMs such as Entity Framework.
• Good understanding of software engineering fundamentals including testing, version control (Git), and CI/CD.
• Experience working with Azure for hosting, deployment and cloud services.
• Comfortable taking ownership, making technical decisions, and improving systems over time.
• Able to balance delivery with long-term code quality and maintainability.

Nice to Have

• Prior experience or exposure to the logistics or courier industry
• Experience with distributed systems, micro-services, or event-driven architectures.
• Familiarity with Docker and container-based workflows.
• Exposure to AI- or data-driven products, even if not hands-on ML work.

What’s on Offer

• A genuinely competitive senior-level salary, plus meaningful equity in a seed-stage AI business (details shared during early interview stages).
• 25 days annual leave, plus bank holidays.
• Access to our EMI share scheme.
• Pension scheme.
• Fully remote working within the UK.
• A collaborative environment where senior engineers have real influence over technical direction and product outcomes.

Candidate Experience

Our interview process is designed to be clear, respectful and efficient.

1. Intro call with a Talent Partner (30–35 mins)
2. Technical interview (video) with Co-Founder & CTO, David (1 hour)
3. Take-home Tech Exercise (2-3hrs max)
4. Final video call with Co-Founder & CEO, Andy, and a Senior Engineer (1 hour)

We aim to give feedback within 24–48 hours at each stage and complete the full process within 1–2 weeks.