Back End Developer - API Integration - Restful API's - Greenfield AI

Backend Engineer – C# .NET | REST APIs | Azure | OAuth | AI Integrations

Birmingham (Hybrid) – UK SaaS Scale-Up – Greenfield API & AI Platform

One of the UK's fastest-growing SaaS scale-ups is investing heavily in a brand-new API and AI integration platform, and they're looking for a Backend Engineer to design and deliver the services that power next-generation AI features, customer products, and third-party integrations.

You'll work with a modern engineering team building RESTful APIs, cloud-native services, and event-driven components in a highly collaborative, product-focused environment.

What you'll be working on (API Development & Integration)

• Designing and implementing RESTful APIs that expose product capabilities to AI services and external partners
• Building production-grade APIs using C# .NET, SQL, and Azure cloud services
• Implementing authentication/authorisation using OAuth and modern security patterns
• Creating clear, well-documented APIs following OpenAPI/Swagger standards
• Contributing to the build and maintenance of a developer portal for API consumers

Skills, Knowledge & Expertise

Essential

• Strong experience in backend engineering with a focus on API development
• Proficiency in C# .NET for building services and APIs
• Solid SQL knowledge — querying, optimisation, and relational schema understanding
• Experience building RESTful APIs for web/mobile applications
• Understanding of API design principles: REST conventions, status codes, error handling
• Familiarity with OAuth, JWT, or API key authentication
• Exposure to Azure and cloud deployment workflows
• Testing mindset — unit tests, integration tests, debugging
• Strong problem-solving and technical troubleshooting skills

Interested?

Apply directly or message me for a confidential chat — even if your CV isn't fully up to date. Happy to walk you through the role, team, and growth path.

Keywords: Backend Engineer, API Engineer, .NET Developer, REST APIs, Azure, OAuth, CI/CD, AI Integrations, SaaS