Senior Software Engineer (C# / .Net) · London ·

LineTen; Greater London; Hybrid; GBP 90,000 - 120,000; Full time

Job summary

LineTen is building a data-driven last-mile network and is seeking a Senior Software Engineer to craft robust backend services and frontend integrations. You will operate in a low-ceremony, high-trust environment, owning critical components and driving long-term software quality.

You will work on distributed systems with a focus on correctness, maintainability, and scalability, using AI-assisted tools responsibly while prioritizing sound design, testing, and thoughtful reviews.

Qualifications

• Proficiency in C# / .NET 8+ with async programming and MediatR/CQRS patterns.
• Strong understanding of distributed systems, event-driven architectures, idempotency, and race conditions.
• Experience with Redis caching and Azure Blob Storage for data management.
• API design focus: RESTful contracts, versioning, webhooks, long-running operations.

Responsibilities

• Develop robust backend services and distributed components.
• Ensure correctness, maintainability, and architectural clarity across systems.
• Collaborate on frontend integrations using SPA frameworks and real-time communication.

Skills

C# / .NET 8+

Distributed systems

Redis caching

Azure Blob Storage

API design

Real-time frontend integration

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.

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