Senior Software Engineer - AI-Driven Legacy Modernisation

RedRock Resourcing; Reading; On-site; GBP 70,000 - 110,000; Full time

Job summary

RedRock Resourcing is seeking a senior software professional to help modernise complex legacy systems using AI-enabled tooling. You will shape the engineering harness, provide AI context and constraints, and work across AI agents and traditional development practices to deliver safer, scalable solutions.

You will collaborate with teams on modernisation strategy, cloud-adjacent improvements and robust testing, while maintaining high quality and performance in complex environments.

Qualifications

• Must have a strong software engineering foundation.
• Experience with large, complex or legacy systems.
• Familiarity with AI-assisted software engineering and AI tooling.

Responsibilities

• Hands-on with complex legacy technology, using AI tooling to tackle technical debt.
• Design the engineering harness to give AI agents the right context, rules and constraints.
• Build repository-level instructions, agent skills, prompts and dynamic context.
• Work with AI-driven development tools such as Claude Code, MCP and related agents.
• Establish automated testing and AI evaluation frameworks to balance speed and quality.
• Create guardrails, sandboxes and CI/CD controls around AI-driven development.

Skills

Software engineering foundation

C#/.NET

AI tooling experience

Legacy systems

CI/CD

Tools

Claude Code

Cursor

GitHub Copilot

Codex

MCP

Job description

RedRock Resourcing is seeking a senior software professional to help modernise complex legacy systems using AI-enabled tooling. You will shape the engineering harness, provide AI context and constraints, and work across AI agents and traditional development practices to deliver safer, scalable solutions.

You will collaborate with teams on modernisation strategy, cloud-adjacent improvements and robust testing, while maintaining high quality and performance in complex environments.