javascript developer jobs in London

Please include a cover note explaining why you and Unboxed will be a good fit together.

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 accessible by default, following WCAG standards
• Participating in show and tells and presenting your work to clients and stakeholders
• Reviewing technical colleagues’ pull requests kindly and constructively
• Adapting to new technologies and workflows, including AI coding tools
• Keeping up to date with relevant technology developments and sharing knowledge with the team

Technical competencies

• Ruby and Ruby on Rails (essential)
• SQL (PostgreSQL or MySQL preferred)
• Git and version control workflows
• HTML, CSS, and accessibility standards
• JavaScript/TypeScript
• Cloud infrastructure (AWS preferred)
• Continuous integration and delivery

Desirable experience

• Experience working in a GDS-style environment or following the GDS Service Manual
• Familiarity with the Discovery, Alpha, Beta, Live delivery framework
• Experience working in an agile team with designers and user researchers
• Open source contributions
• Experience setting up and maintaining UNIX systems
• Experience working with AI tools and agentic workflows

Core competencies and behaviours

We expect everyone at Unboxed to be:

• Naturally collaborative
• Good communicators (written and verbal)
• Creative problem solvers
• Adaptable
• Comfortable with uncertainty and complexity
• Curious and questioning
• Active listeners
• Empathic, humble and generous
• Open and honest
• Always learning
• Passionate about our work
• Reflective, on yourself and the situation

How we workFlexible, hybrid working

We’ve adapted our working practices and London office space to support hybrid working. The whole team works in our London office a minimum of two days a week. We trust our team to do the work they need to do and to collaborate closely. If you need to flex around caring responsibilities or other commitments, we’ll work with you to find the right balance.

Inclusion and wellbeing

At Unboxed, we strive to create an inclusive workplace where people can thrive and feel they belong. We promote a good work-life balance, open communication, and positive working relationships.

Our success depends on our team, and we want each member to feel fulfilled and valued. As part of your progression, you can expect:

• Monthly reflection sessions
• Six-monthly director check-ins
• An open and coaching-led approach
• Weekly development and design learning sessions

We are an equal opportunity employer and are committed to increasing diversity within Unboxed. We recognise that not everyone will have had the same opportunity to gain relevant experience, and welcome applications from UK residents who may have felt excluded from such a role in the past, whether due to age, gender, ethnicity, visible or invisible disability, neurodivergence, education, religion or belief, sexual orientation, or family and care commitments.

Salary bands

We use salary bands to ensure that everyone at Unboxed gets paid fairly in relation to others at the company. We assess which band you are in according to skills, competencies and experience.

Other benefits

• 25 holiday days per year, on top of the bank holiday allowance
• 10 Innovation Days per year to explore your own ideas
• Holiday flexibility and loyalty bonus benefits
• Maternity and Shared Parental Leave policies
• A company-wide peer-to-peer mentoring programme
• A generous conference budget
• Flexible working hours and location
• An informal culture of growth
• Monthly ‘Linkers and Thinkers’ idea-exploring lunches
• Weekly ‘Design Club’ to share wider thoughts, ideas and opinions with the team

Application process

To apply, please submit your application to work@unboxed.co. Please include a cover note explaining why you think Unboxed is the place for you, a work history in the form of a CV or LinkedIn profile, and some examples of your work in the form of a portfolio, website, or case studies.

If we think there could be a good match, the process is:

• Initial 30-minute call to discuss the role (5–10 candidates)
• Tech test
• 60-minute interview with a multidisciplinary Unboxed team to discuss your experience, values and approach (3–5 candidates)
• Pairing session to discuss and extend what you built in your tech test (3–5 candidates)
• Offer made or feedback provided

We would expect to complete this process within three weeks of the application closing date.

Pay: £53,182.00-£60,000.00 per year

Application question(s):

• Are you able to work in the office in London and on client site at least 2 days a week, ocassionally more?
• Do you have at least 3 years, full-time and commercial, Ruby-on-Rails experience working in teams of more than 2 people? [Excluding projects during your education]
• Please include a cover note explaining why you and Unboxed will be a good fit together. Have you done so?
• Have you been resident in the UK for 5 years? This is a mandatory security clearance requirement for the job.

Work Location: In person