Senior Backend Engineer, Identity & Auth (C#/.NET)

DeepL; Greater London; Hybrid; GBP 60,000 - 100,000; Full time

Benefits offered by this job

Hybrid work model

30 days of annual leave

Mental health resources

Location-based benefits

Virtual shares

Job summary

DeepL, a global AI product and research company, is hiring for a London-based Engineering role in Identity and Access Management. You will design and build complex identity features, own services end-to-end, and optimize authentication/authorization for a secure user experience.

The role emphasizes system design, production operations, and collaboration with cross-functional teams. You will work in a hybrid model, leveraging AI tools to accelerate boilerplate code and testing, while maintaining

Qualifications

• Deep expertise designing scalable backend systems and distributed architectures.
• Experience with high-scale distributed systems in production.
• Strong system design skills.
• Familiarity with B2B SaaS identity, authentication (SSO/OIDC), authorization, security, and auditing.
• Experience owning services end-to-end, including production operations, incident response, and on-call.
• System-thinking mindset with an understanding of failure modes and architecture at scale.
• Backend expertise in C# / .NET, with roughly 80-90% backend work.

Responsibilities

• Architect and build complex, user-facing features across our identity stack.
• Own business-critical systems from problem definition through architectural design, deployment, and production reliability.
• Build reliable authentication and authorization systems with a user-friendly experience.
• Lead incident response and continuously improve code quality and operational health.
• Collaborate with Identity, Product Management, Support, and adjacent teams.
• Lead designs, scoping, and problem-solving for hard product and technical challenges.
• Choose technology that solves customer problems with long-term maintainability.
• Use AI tools to speed up boilerplate, testing, and debugging for higher-value architecture.

Skills

C# / .NET backend

Backend development

Distributed systems

System design

Authentication / Authorization (SSO/OA

Incident response / on-call

AI-assisted coding

React / JavaScript (optional)

Tools

Kubernetes

GitHub

JIRA

ASP.NET

Job description

DeepL, a global AI product and research company, is hiring for a London-based Engineering role in Identity and Access Management. You will design and build complex identity features, own services end-to-end, and optimize authentication/authorization for a secure user experience.

The role emphasizes system design, production operations, and collaboration with cross-functional teams. You will work in a hybrid model, leveraging AI tools to accelerate boilerplate code and testing, while maintaining