Senior .NET Backend Engineer: API & Integrations (Remote)

Avendra International - Europe; Greater London; Hybrid; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Flexible remote-first working

London in-person meetings

Job summary

Avendra International - Europe is seeking a Senior Backend Developer to scale our eProcurement SaaS platform. You will design, build and maintain high-performance backend services in C# and .NET, and implement secure REST APIs.

This role is remote-first in the UK with occasional London offices for meetings and workshops. You will own integrations with ERP, procurement and finance systems, handle OAuth/OpenID security, and drive reliability.

Qualifications

• Strong commercial experience developing applications with C# and .NET
• Proven experience designing, building and supporting RESTful APIs and system integrations
• Experience working within Agile software development environments
• Knowledge of API security, scalability and modern software engineering practices
• Strong problem-solving skills with the ability to work effectively in a remote-first team environment

Responsibilities

• Design, develop and maintain high-performance backend services using C# and .NET
• Build and evolve secure, scalable RESTful APIs for customers, partners and internal platforms
• Develop integrations with ERP, procurement, finance, eCommerce and other third-party systems
• Deliver secure API connectivity using OAuth 2.0, OpenID Connect and token-based authentication
• Design resilient, scalable solutions capable of supporting high transaction volumes
• Develop event-driven and message-based integrations using modern architectural patterns
• Troubleshoot production issues, identify root causes and implement sustainable improvements
• Contribute to technical design discussions, code reviews and engineering best practices

Job description

Avendra International - Europe is seeking a Senior Backend Developer to scale our eProcurement SaaS platform. You will design, build and maintain high-performance backend services in C# and .NET, and implement secure REST APIs.

This role is remote-first in the UK with occasional London offices for meetings and workshops. You will own integrations with ERP, procurement and finance systems, handle OAuth/OpenID security, and drive reliability.