Senior Engineer (Ruby & AI)

Surventrix Systems is an established software provider serving the UK financial and surveying markets. Our products help businesses improve their processes, increase operational efficiency, and reduce risk.

We are developing new products for new market segments while modernising and improving our existing platforms. This includes adopting new technologies, AI-assisted development practices, intelligent agents, and new approaches to solving complex engineering problems.

We are looking for an experienced, hands-on Senior Full-Stack Engineer with strong software engineering fundamentals, excellent problem-solving skills, and sound technical judgement.

Beyond building new features, you should be comfortable working on complex production systems, investigating performance bottlenecks, managing application upgrades, reviewing code critically, and improving the overall quality and reliability of our software.

Ruby and Rails experience is strongly preferred. We value engineering depth, adaptability, and the ability to solve difficult problems over expertise in any particular language or framework.

What you will do

• Design, develop, test, and release complex features across the full stack, from backend services and databases to APIs and front-end interfaces.
• Investigate and resolve performance bottlenecks, difficult bugs, and production issues.
• Plan and implement framework, dependency, and application upgrades while managing compatibility and operational risks.
• Optimise database queries, background processing, memory usage, and application performance.
• Refactor and modernise existing codebases to improve maintainability, scalability, and reliability.
• Conduct thorough code reviews, identifying correctness, performance, security, design, and maintainability concerns.
• Use AI-assisted development tools effectively for implementation, investigation, debugging, refactoring, and testing.
• Contribute to AI-powered product features and agent-based workflows where they provide meaningful value.
• Improve code quality, testing, automation, monitoring, and engineering practices.
• Participate in technical discussions, contribute to architectural decisions, and support other developers through constructive feedback and mentoring.
• Take ownership of challenging technical work from investigation and design through to production deployment.

What we are looking for

Strong engineering fundamentals

You should have substantial professional software development experience, typically 7+ years, with a solid understanding of:

• Data structures, algorithms, and object-oriented programming.
• Software architecture, design principles, patterns, and technical trade-offs.
• Database design, SQL, indexing, transactions, and query optimisation.
• APIs, web applications, asynchronous processing, and distributed systems.
• Performance profiling, debugging, caching, and resource management.
• Testing, application security, monitoring, and production reliability.
• Source control, collaborative development, and code review practices.

We value engineers who can explain their technical decisions, recognise weaknesses in existing implementations, and choose pragmatic solutions rather than simply applying familiar patterns.

Experience with production systems

You should have hands-on experience maintaining and improving established applications, including investigating complex issues, upgrading frameworks and dependencies, optimising performance, and safely refactoring existing code.

You should be comfortable identifying root causes, evaluating technical risks, and delivering reliable solutions without requiring constant guidance.

Full-stack development experience

You should be comfortable working across backend services, databases, APIs, and front-end technologies, with experience taking features from initial requirements through to production.

Experience with Ruby or Ruby on Rails is strongly preferred, but not required. Developers with strong expertise in another mature framework are encouraged to apply, provided they are willing and able to become productive in Ruby and Rails.

Code reviews and technical judgement

You should have meaningful experience reviewing other developers' code, identifying subtle bugs, performance issues, poor abstractions, and maintainability concerns.

We are looking for someone who can challenge technical decisions constructively, suggest better alternatives, and help maintain high engineering standards.

AI-assisted development and agents

You should be proficient with AI development tools such as Cursor, Claude Code, or similar coding agents.

We expect you to use these tools efficiently, manage context and token usage thoughtfully, critically validate generated code, and retain ownership of technical decisions and code quality.

You should also have a practical understanding of AI agents, including tool calling, multi-step workflows, context management, structured outputs, and reliability.

Technical collaboration and ownership

You should be self-motivated, comfortable working independently, and capable of taking ownership of complex technical challenges.

You should communicate clearly, collaborate effectively, and contribute to technical design discussions. Some experience mentoring developers, guiding technical initiatives, or contributing to architecture decisions would be beneficial, with opportunities to take on greater technical leadership responsibilities over time.

Nice to have

• Professional Ruby on Rails experience, including Rails 8, Stimulus, Turbo, or Hotwire.
• Experience with PostgreSQL, Redis, background jobs, and application performance optimisation.
• Familiarity with Minitest, test-driven development, and automated testing.
• Experience with AWS, Heroku, CI/CD, and production monitoring tools.
• Experience modernising established applications or leading complex technical upgrades.
• Experience mentoring developers or guiding a small engineering team.
• Experience building AI-powered applications, agent workflows, or language-model integrations.
• Experience in financial services, surveying, property technology, or regulated industries.

Why you will enjoy working here

• Meaningful engineering challenges: Work on complex production systems, performance optimisation, modernisation, and new product development.
• Technical ownership: Take responsibility for challenging engineering work and influence technical decisions.
• AI-native engineering: Work with modern AI coding tools and contribute to practical AI-powered product capabilities.
• Growth opportunities: Develop greater influence over architecture, engineering practices, and technical leadership.
• Autonomy: We do not believe in micro-management. You will have the freedom to take ownership, challenge assumptions, and contribute your ideas.
• Remote-first flexibility: The role can be performed remotely from within the UK.
• Visible impact: Work within a focused team where your contributions directly affect our products and customers.

We are looking for a seasoned engineer who enjoys solving difficult problems, takes pride in writing and reviewing high-quality code, and wants to make a meaningful contribution to our products and engineering team.