Senior Software Engineer (C# / .Net) London

What we do

LineTen is on a mission to crack the code on urban delivery. By leading with our values and putting carrier partners first, we are paving the way for better delivery experiences. LineTen is a new approach to delivery with a free carrier API and an operations management platform for shippers. We're building the first global data-driven last-mile network that has the potential to solve industry-wide problems.

We're hiring a Senior Software Engineer who treats software as a craft, not a checklist. You'll join a small, high-trust team where ownership is expected, curiosity is encouraged, and outcomes matter more than activity. This is not a ticket-factory role: you'll be expected to think critically, challenge assumptions, design robust solutions, and take responsibility for their long-term success.

You'll work across backend services, distributed systems and frontend integrations, with a strong focus on correctness, maintainability and architectural clarity. You'll also use AI-assisted development tools responsibly, understanding that speed only matters when paired with strong design, testing and review discipline.

How you'll work

• Operate with high ownership in a low-process environment

• Proactively look for what can be improved rather than waiting for direction

• Value correctness, clarity and maintainability over "it just works"

• Work outside strict role boundaries when needed, without feeding burnout culture

• Communicate technical decisions clearly and push back constructively when required

Core technical skills

• C# / .NET 8+, Entity Framework Core, async/await, MediatR / CQRS

• Strong understanding of distributed systems: consistency models, event-driven patterns, idempotency, race conditions

• Experience with Redis caching, Azure Blob Storage, and data-modelling trade-offs

• API design: RESTful contracts, versioning, webhooks, long-running operations (202 Accepted patterns)

• Real-time & frontend integration: SignalR / WebSockets, SPA frameworks (Vue / Nuxt or similar), TypeScript

What good looks like

• You leave systems clearer, more correct, and easier to evolve

• Problems are solved at the right level, not patched over

• Trade-offs are explicit and understood

• Other engineers trust your judgement and the quality of your code