Senior Software Engineer (C# / .Net)

LineTen; Greater London; On-site; GBP 50,000 - 70,000; Full time

Job summary

A tech-driven delivery company in the UK is seeking an experienced developer skilled in C# and .NET to enhance their urban delivery solutions. You will operate in a low-process environment, responsible for improving system quality and tackling technical challenges proactively. The role requires expertise in distributed systems, API design, and real-time integrations. Join a mission to transform the delivery experience with a dynamic team committed to clarity and correctness in code.

Qualifications

• Strong understanding of distributed systems, including consistency models.
• Experience with API design for RESTful contracts and versioning.
• Proficient in real-time integration using SignalR or WebSockets.

Responsibilities

• Operate in a low-process environment with high ownership.
• Communicate technical decisions clearly and constructively.
• Aim for correctness and maintainability in code.

Skills

C# / .NET 8+

Distributed systems

Redis caching

Azure Blob Storage

API design

SignalR / WebSockets

TypeScript

Job description

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.

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