Software Engineer
Software C# Engineer
Salary: £50ph (Inside IR35)
12 months contract role - beginning April
Remote role with 1 day per month on-site at the Rugby office
As Gi Group, we are supporting an international company delivering mission-critical solutions used daily by emergency services across the UK and Europe. The project focuses on Guardian, a call-taking and dispatching platform that enables 999 and 112 operators to respond effectively when every second matters.
As a Software C# Engineer, you will join an Agile engineering team working on complex, real-time communication systems that go far beyond standard CRUD applications. You will contribute to the core Guardian platform while also taking ownership of expansion products interfacing with 3GPP-compliant user equipment.
THE ROLE:
Your responsibilities will include:
- Designing and developing C# components for high-concurrency SIP signaling and session management
- Handling complex SIP headers and MIME bodies to support advanced call-handling features
- Implementing real-time media processing using RTP/RTCP for Mission Critical Voice and Video
- Developing MCData services, including and SIP MESSAGE-based communication
- Managing XCAP configuration retrieval and XML document handling
- Ensuring secure communications through OIDC authentication and MIKEY-SAKKE encryption
- Collaborating closely with senior product leads and influencing the technical direction of the platform
THE CANDIDATE:
We are looking for an experienced engineer who is comfortable working with network-centric, highly available systems and real-time communication technologies.
- 4+ years of commercial experience with C# and .NET (.NET Framework and/or .NET Core)
- Strong background in asynchronous and network-focused programming
- Hands-on experience with WCF, SignalR, Entity Framework, ASP.NET, WebAPI
- Solid understanding of SIP protocol stacks and RTP/RTCP
- Experience working with complex XML schemas (XSD) and multipart/mixed MIME messages
- Good knowledge of OOP, SOLID principles, and Agile / CI/CD practices
Nice to have:
- Familiarity with 3GPP standards such as MCPTT or other MCX specifications
- Experience with SRTP, TLS, or key management systems (KMS)
- Previous exposure to emergency services environments, ESN, or police/fire control rooms