Senior Backend Developer (.NET | AI-First SaaS Platform) in Portsmouth

Compensation: Competitive, based on location and experience

Location: UK or Turkey (Hybrid – Office & Remote)

Keepnet is an AI-driven SaaS platform experiencing strong, sustained growth in the UK with growing global momentum, helping organisations manage human cyber risk at scale.

With Agentic AI live in production, Keepnet runs autonomous systems that plan, build, and operate security awareness and human risk workflows, supported by strong guardrails and observability.

We're looking for a Senior Backend Developer who wants to build production-grade backend services that power these systems, working in a multinational, AI-first engineering team where quality, ownership, and long-term thinking matter.

What You'll Do

• Design, build, and maintain scalable backend services for Keepnet's Human Risk Management platform.
• Build clean, modular APIs that integrate internal services and third-party systems to enable automation, reporting, and security workflows.
• Develop testable, maintainable codebases using principles such as Clean Architecture, DDD, and TDD.
• Own the full development lifecycle: design, implementation, CI/CD (Azure), and post-release monitoring.
• Work on distributed and asynchronous systems using message queues, background workers, and event-driven workflows.
• Use observability signals (logging, metrics, tracing, tools like Sentry) to proactively detect, diagnose, and prevent production issues.
• Collaborate closely with frontend, product, and customer-facing teams to deliver features that solve real customer problems.
• Participate in Agile ways of working, focused on iteration, ownership, and continuous improvement.

What We're Looking For

• 8+ years of experience building backend systems with .NET.
• Strong understanding of API design, distributed systems, and asynchronous architectures.
• Experience with SQL and NoSQL databases (PostgreSQL preferred), caching, and queuing systems.
• Familiarity with cloud environments and DevOps practices (Azure preferred).
• Comfort working on production SaaS platforms, with ownership beyond deployment.
• Experience using AI-assisted development tools (e.g. Cursor or similar) to support code exploration, refactoring, testing, or design discussions—while maintaining strong engineering judgment.
• A strong sense of ownership and production accountability, including monitoring, debugging, and continuous improvement.
• Ability to understand product and business context, making pragmatic technical decisions that balance user value, risk, and long-term goals.
• A security-conscious mindset, building systems that are secure by design.

Life at Keepnet

At Keepnet, engineering is about craft, collaboration, and impact.

What you can expect:

• Hybrid Working: A balance of in-office collaboration and remote focus time.
• Thoughtful Engineering: Time and space to design systems properly, not just ship quickly.
• Global Context: Work on a multinational SaaS platform used across multiple regions.
• AI-First Environment: AI-assisted development and production-grade AI systems are part of everyday work.
• Annual Leave: 25 days (+1 per year of service).
• Health & Well-being: Gym support and cycle-to-work scheme.
• Team Culture: Monthly team lunches and quarterly offsites.
• Continuous Learning: Learn from experienced peers and grow your skills over time.

Why This Role Is Different

This role is for engineers who:

• Care about system design and long-term maintainability.
• Enjoy working with experienced peers who challenge each other constructively.
• Prefer preventing incidents over reacting to them.
• Want to build software used by real customers at real scale.
• Believe good engineering is as much about ownership and judgment as it is about code.

If that sounds like you, we'd love to talk.