Senior Software Engineer – C# / .NET
Job description
Full-stack software engineer role supporting Inventory Lab, an e-commerce seller product for inventory, listings, accounting and operational workflows. The engineer owns features across C#/.NET backend systems and Vue.js/TypeScript front ends from design to production.
At a glance
- Employment
- Full-time
- Work mode
- Remote · United Kingdom
- Pay
- GBP 110,000 / year
What you'll do
- Take ownership of features across Inventory Lab's C# and .NET-based systems, delivering them from initial design through to production
- Design, develop, and maintain clean, scalable backend services, APIs, and application components using C# and the .NET ecosystem
- Work with modern .NET technologies, including ASP.NET and ASP.NET Core, to build and maintain reliable, high-performance web applications and services
- Write maintainable, well-tested code that supports the product's evolving requirements
- Develop and maintain front-end features using Vue.js and TypeScript, building responsive, intuitive, and maintainable user interfaces that integrate with backend APIs
- Take ownership of full-stack features end to end, from designing backend services and data models to implementing front-end components, managing application state, and ensuring a consistent user experience
- Collaborate with Product, QA, and DevOps to deliver reliable, performant features across the entire application stack
- Operate independently within a defined scope, making sound technical decisions and balancing delivery speed with long-term quality
- Actively improve existing systems, debug production issues, identify root causes, and implement durable fixes
- Contribute to technical discussions, help evolve architecture within your domain, and raise engineering standards through thoughtful code reviews
What we're looking for
- 6–8+ years of professional software engineering experience
- Strong proficiency in C# and experience building production-grade applications
- Strong understanding of the .NET platform, including its runtime, libraries, and application development ecosystem
- Experience developing web applications and backend services using ASP.NET and ASP.NET Core
- Experience developing modern web applications using Vue.js or React, including component-based architecture and reusable components
- Experience building responsive, accessible user interfaces and integrating front-end applications with REST APIs, and maintaining backend services
- Solid understanding of system design, application architecture, and scalable software development patterns
- Experience working with SQL databases, relational data models, and query optimization
- Familiarity with cloud infrastructure: AWS or Azure
- Experience debugging production systems, investigating root causes, and resolving issues independently
- Comfortable working with Git, code reviews, automated testing, and collaborative development workflows
- Ability to work effectively within an existing codebase and improve code quality without over-engineering
- Strong ownership mindset and consistently delivers high-quality work
- Makes pragmatic technical decisions, understanding when to prioritize speed and when to invest in scalability, reliability, and maintainability
- Understands the practical application of C# and the .NET ecosystem, choosing appropriate frameworks and patterns to build reliable software
- Comfortable working with existing systems, identifying opportunities for improvement, and delivering solutions that balance immediate business needs with long-term technical quality
- Thrives in a product-led environment and cares about the customer impact of what they build
- Communicates clearly, collaborates effectively across teams, and looks for ways to improve both the product and engineering processes
Your team
Inventory Lab
A product used by e-commerce sellers to manage inventory, listings, accounting, and operational workflows.
Benefits
- Salary: £110,000 per year
- 25 days PTO
- Healthcare & Pension benefits
- Opportunity to join company-wide offsites
- Regular rate reviews and bonus opportunities
- Fully remote/hybrid working
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About Threecolts
A software suite built for consumer brands
Threecolts is a software suite built for consumer brands, helping them recover revenue, operate more efficiently and grow across major retailers and marketplaces. Its largest business, Margin Pro, helps brands recover money owed to them by retailers and marketplaces such as Amazon, Walmart and Target by managing disputes on their behalf. Alongside this, Threecolts is building and scaling newer products, including AI Operator and Retail 365, while continuing to grow its portfolio of subscription products across its customer base.
Key facts
- 340 people across 33 teams
- Software
- Global team of 340 people across 33 teams
- Grown through 24 acquisitions
- Flat structure giving people real ownership and the ability to move quickly
- AI is embedded in how we work across the business
Partners & customers