Ruby on Rails Developer - mid level

About the company

Unboxed is an established and well respected design and digital product development agency based in London. We help our clients solve knotty problems, increasing business agility and improving user outcomes. Our multidisciplinary teams combine core expertise in design and software development with specific domain knowledge to deliver positive change and create meaningful impact.

We have focused in recent years on delivering technology-enabled services in the public sector, working with local authorities, the NHS, and housing and planning bodies. We work in a GDS-influenced way: agile, user-centred, and focused on real outcomes rather than outputs.

Our strategic aim is to expand our influence across public, private and the third sector to address systemic problems in areas such as the built environment and neighbourhood health.

We are looking for someone with 3+ years’ experience to join our development team as a mid-level Developer, working across a range of impactful public sector projects.

About the role

This is a hands-on development role for someone who cares about why they’re building something, not just what they’re building. You’ll be a core member of a small, cross-functional team alongside designers, user researchers, and delivery managers, working closely together throughout delivery.

You’ll work primarily in Ruby on Rails, contributing to real products used by real people in public services. We don’t build for high-traffic consumer apps or optimise for scale as an end in itself. We build things that work, that are tested, that are accessible, and that solve genuine user needs.

We’re looking for someone who is collaborative, curious, and comfortable working in an environment where requirements evolve and the right approach is often discovered through doing. You should be at home in a GDS-style delivery environment, familiar with agile ways of working, and genuinely interested in the outcomes your code enables.

The successful candidate will also be available for out-of-hours support on a rota basis (for an extra payment), which will require working knowledge of AWS or a similar cloud provider.

What you’ll be doing

Delivering working software that users can rely on

You ship tested, accessible, maintainable code across the full delivery lifecycle. The team knows that when something leaves your hands, it works and won’t quietly break something else. You default to simple, well-understood solutions, and you know when a prototype is the right tool and when it isn’t.

Helping the team understand and solve the right problems

You engage with user research and design work, not just the technical brief. You contribute to decisions about what to build and why, and you surface technical constraints early enough that they inform design rather than derail it. Designers and researchers see you as a genuine collaborator, not a ticket-taker.

Keeping delivery moving without letting quality slip

You communicate proactively, flag blockers before they become blockers, and help your team make good decisions by sharing what you’re learning. Your code reviews are useful, your pull requests are well-scoped, and the people you work with find it easy to stay in sync with you.

Bringing the best available tools to the team’s work

You stay curious about the broader landscape of tools and techniques available to you, and you actively bring useful ones into the team’s practice. That includes AI coding assistants, but also anything else that genuinely improves how you work. You evaluate new tools critically rather than chasing novelty, share what you learn, and help colleagues get value from them too. The team’s collective capability grows partly because of you.

Key activities

Day to day, you’ll be:

• Building and maintaining Ruby on Rails applications across Discovery, Alpha, Beta, and Live phases
• Working directly with designers to turn designs and prototypes into functional, accessible products
• Participating in user research sessions and contributing to decisions about what to build
• Writing and maintaining automated test suites as part of normal delivery
• Reviewing and adapting existing codebases, including legacy systems
• Working with Git, version control workflows, and continuous integration pipelines
• Contributing to and consuming modern APIs
• Demonstrating best-in-class security practices, especially when handling personal or public data
• Making products a…