Senior Developer

Isms; Brighton; Hybrid; GBP 70,000 - 90,000; Full time

Job summary

Isms is seeking a Senior Software Developer to join a small, capable engineering team in Brighton. You’ll work with the CTO, Tech Lead and Product Team to deliver roadmap work, improve architecture, and shape AI usage across engineering in a practical, measurable way.

You’ll thrive moving between legacy and modern patterns and contribute beyond delivery in a fast-growing SaaS platform with global customers. Expect ownership and real scope in a close-knit team.

Qualifications

• 5+ years of relevant experience.
• Strong Ruby fundamentals and sound object-oriented design.
• Strong backend engineering skills, with frontend concepts.
• Experience in a mature monolith, handling tech debt and refactoring.
• Strong SQL skills and ability to write complex queries.
• Experience contributing to architecture and technical direction.
• High autonomy, initiative and product awareness.
• Confidence using AI for coding, refactoring, testing and workflows.
• Good judgment about where AI helps and where it doesn’t.
• Clear, honest communication about how you work best.

Responsibilities

• Build and maintain product features in Rails.
• Contribute to architecture decisions and evolve the platform.
• Work across legacy and modern parts of the application.
• Improve performance, maintainability and team productivity.
• Support the team through code review, pairing, mentoring and planning.
• Help define AI-augmented workflows for the team.

Skills

Ruby fundamentals

Backend engineering

Monolith experience

SQL proficiency

Architecture and tech direction

Autonomy & initiative

AI for coding & testing

Communication on working style

Tools

Stimulus

Turbo

Hotwire

Event-driven architecture

Job description

This role suits someone who is comfortable taking existing software to the next level, can move between legacy and modern patterns without drama, and is motivated by making a real contribution in a small team.

Help us scale smarter, faster, and with purpose

Since 2005, we’ve helped organisations achieve their goals through simple, sustainable, and scalable information security. What started as a solution to help UK police forces share sensitive data securely has grown into a global SaaS platform, IO – trusted by thousands of businesses worldwide.

We’re growing fast. Backed by private equity investment and with customers across the UK, Europe, the US, and APAC, we’re expanding our team and doubling down on our mission: to set the standard for information security management and deliver compliance confidence through our exceptional people, process, and platform.

That’s where you come in.

About the role

We’re hiring a Senior Software Developer to join our small, capable engineering team.

You’ll work closely with our CTO, Tech Lead and Product Team to deliver roadmap work, improve the architecture where it matters, and help shape how AI is used across engineering in a practical, measurable way.

This role suits someone who is comfortable taking existing software to the next level, can move between legacy and modern patterns without drama, and is motivated by making a real contribution in a small team.

What you’ll be doing

• Build and maintain product features in Ruby on Rails
• Contribute to architecture decisions and help evolve the platform over time
• Work confidently across legacy and modern parts of the application
• Improve performance, maintainability and team productivity
• Support the team through code review, pairing, mentoring and technical planning
• Help define and improve AI-augmented engineering workflows for the whole team
• Contribute ideas, not just delivery

Our stack

Our core application is a long-running Rails monolith with more than 15 years of history. Some older patterns still exist, but new development is moving in a clear, modern direction.

• Rails 8.1
• Ruby 4.x
• MySQL 8.x
• GitHub Actions
• Cypress end-to-end testing
• Turbo
• Literal::Types
• Service objects, moving towards dry-rb libraries
• Action Policy
• Rails Event Store
• Delayed Job
• New Relic
• Terraform and Kubernetes on AWS

AI-augmented engineering, without the slop

We’re serious about using AI to improve speed, quality and leverage across engineering. It isn’t a nice-to-have for us; it’s how we work now. We generate with AI, but everything is reviewed and everything carries original thought.

We want someone who already uses AI heavily in their engineering work, is passionate about it, understands its strengths and limits, and can help us build better workflows around it.

What you bring

Must-haves

• 5+ years of relevant experience
• Strong Ruby fundamentals and sound object-oriented design skills
• Strong backend engineering skills, with working knowledge of frontend concepts
• Experience working effectively in a mature monolith, treating tech debt and refactoring as part of everyday work
• Strong SQL skills and confidence writing and understanding queries
• Experience contributing to architecture and technical direction
• High autonomy, initiative and product awareness
• Confidence using AI for coding, refactoring, testing, documentation and workflow improvement
• Good judgement about where AI helps and where it doesn’t
• Clear, honest communication: you tell us how you work best and adapt to how others like to work

Nice-to-haves

• Experience with Stimulus, Turbo or Hotwire
• Experience with event-driven architecture
• Familiarity with security and compliance domains
• Familiarity with ISO 27001 or similar standards
• Experience with agentic workflows, automation design or evals
• Personal projects that show thoughtful use of AI

Why you’ll love it here

Our exec team is hands-on in the code and brings real industry expertise. They care about growth, and about how we achieve it. We win and lose together.

We’re a small engineering organisation, so this role has real scope and real responsibility. We value people who contribute beyond the ticket in front of them, collaborate well and help improve how the team works.