Independent · AI-Native · Made in England

Great software, delivered faster. Built to last.

Door Fifteen is an independent software consultancy for ambitious organisations. We design and engineer bespoke digital products that create measurable value, embedding AI into every aspect of delivery, and leaving your teams stronger than we found them.

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Trusted by ambitious organisations across regulated industries

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Why Door Fifteen

Technology is our how. People are our why.

For ambitious enterprises and scale-ups: we combine world-class engineering, industry expertise and a people-centric mindset to harness technology for meaningful change, delivering the most challenging projects with a minimum of fuss.

🚀

Build the right thing, the right way

Human-centred product delivery from vision to launch: multidisciplinary teams take you from idea to a digital product customers love in as little as 100 days, without compromising on quality or safety.

🧭

Modernise with confidence

We transform legacy technology and simplify technical architecture, delivering fully-compliant, best-in-class solutions on time and within budget, with uptime and reliability assured.

🌱

Grow your own capability

We work as one team for the long term, coaching and upskilling your people as we go, so you close the digital skills gap and keep shipping long after we leave. You keep the IP, the codebase, and the savings.

AI-Native Delivery

Transforming businesses with intelligence.

By embedding AI into every aspect of delivery, we redefine how organisations drive efficiency. Our AI-native delivery framework pairs cutting-edge technology with deep subject matter expertise, enabling your teams to ship faster, with continuous improvement and scalable operations built in.

  • Custom AI designed for your business, deployed on your cloud and owned by you
  • Four weeks to working software, with measurable ROI
  • Agentic automation that runs your most expensive operations for a fraction of the cost
  • Citizen- and customer-centred AI, delivered responsibly in regulated environments
100days from idea to launched product
4 wksto first working software
70%lower delivery cost with AI-augmented teams
96%of clients would recommend us

“Door Fifteen are the benchmark every other supplier needs to aspire to. Collaborative, straightforward, and completely focused on real results. They delivered the outcomes on time and within budget.”

Placeholder testimonial · Chief Digital Officer, Client Name
Ready when you are

The way in to better software.

Whether you're validating a new product, modernising legacy systems, or scaling an AI capability, open the door and let's talk about the impact you want to make.

Start a conversation
Services

A complete software partner, from first idea to ongoing support.

From initial consultancy and design right through to deployment, optimisation and managed support, our award-winning strategists, designers and engineers unlock new value at every stage.

🎯

Product Strategy & Design

Identify the right problem to solve and design the right thing. We validate your digital product vision and craft seamless, engaging experiences customers actually want.

  • Discovery & user research
  • Product vision & roadmaps
  • UX/UI & service design
⚙️

Bespoke Software Engineering

Innovative, bespoke software engineered to drive measurable value, delivered by teams with the deep technical experience to handle the most challenging builds with a minimum of fuss.

  • Full-stack web development
  • APIs, middleware & integrations
  • Continuous delivery pipelines
🤖

AI & Data

Custom AI agents built for your workflows, deployed on your cloud and owned by you. Mission-critical outcomes from data platforms, machine learning and agentic automation.

  • AI strategy & agentic transformation
  • Data engineering & analytics
  • ML & intelligent automation
☁️

Cloud & Platform Engineering

Simplify your architecture and construct a future tech roadmap. Cloud-native platforms engineered for scale, security and speed of change.

  • Cloud migration & modernisation
  • Platform & DevOps engineering
  • Architecture & tech strategy
📱

Mobile & Multi-Platform

Experts in everything mobile: transformational apps and connected experiences that remove complexity across technology stacks and delight users at scale.

  • Native & cross-platform apps
  • App strategy & optimisation
  • Connected devices & beyond
🛡️

Modernisation & Managed Services

Transform legacy technology and keep it performing. We ensure uptime and reliability with fully-compliant solutions and long-term support partnerships.

  • Legacy modernisation
  • Managed services & support
  • Quality engineering & testing
Sector depth

Deep experience in complex, regulated industries.

Financial ServicesGovernment & Public SectorHealth & Life SciencesRetail & eCommerceEnergy & UtilitiesTravel & Transport

Not sure where to start?

Book a free discovery session and we'll help you identify the right problem to solve, and the fastest, safest route to solving it.

Book a discovery session
Our Approach

A different kind of partnership: one team, working for the long term.

People-powered transformation with impact beyond the bottom line. We collaborate closely with your organisation, embed alongside your people, and measure ourselves on the outcomes you care about.

How we work

Fast to value, built to last.

1

Discover

We start by understanding your business, your users and your industry, identifying the right problem to solve before a line of code is written.

2

Deliver

Embedded, multidisciplinary squads get you to working software in four weeks and a launched product in as little as 100 days, shipping continuously, without compromising quality or safety.

3

Scale

Teams scale up when the work demands more, down when it doesn't. We optimise performance, ensure reliability, and keep improving what we've built together.

4

Empower

We coach and upskill your people as we go, establishing a digital product culture, so the capability stays with you. You keep the IP, the codebase and the savings.

What makes us different

  • Independent. Advice you can trust, free of vendor lock-in or corporate agendas.
  • AI-native. AI-augmented delivery in everything we do, not bolted on afterwards.
  • Outcome-based. We measure success in your results, not our billable hours.
  • Transparent. Straightforward, collaborative, and completely focused on real results.
  • Purpose-driven. Technology that improves things for people, places and the planet, with sustainable solutions ready for an ever-evolving world.

Our promise

Innovation, experience and pragmatism: measurable results with every project. Work of exceptional quality, delivered on time and within budget, by happy, engaged people who are totally committed to your satisfaction.

Outcomes, not promises

Measurable value, from day one.

2×faster delivery with AI-augmented engineering
60%reduction in engineering time on modernisation work
1/3the cost of running expensive manual operations
100%of the IP and codebase stays with you

See how one team could work for you.

Tell us about your biggest challenge and we'll show you how an embedded Door Fifteen squad would tackle it.

Talk to us
Our Work

Digital products that matter, and that customers love.

We work at the heart of organisations, on the tough, complex challenges that get them closer to their customers. A selection of what we've designed, engineered and scaled together. (Template placeholders. Replace with your own case studies.)

Retail & eCommerce

Reinventing mobile commerce for a national retailer

A best-in-class mobile experience, engineered from strategy to launch in 100 days, removing complexity across the technology stack and driving loyalty at scale.

+38%conversion uplift in the first quarter after launch
Government & Public Sector

A citizen-centred digital service, delivered at national scale

Modernising legacy systems into a cloud-native platform with usability and accessibility at its core, helping a public body make a positive impact through technology, fast.

4.2mcitizens served in year one, on time and within budget
Financial Services

Agentic AI modernisation for a regulated fintech

Custom AI agents deployed on the client's own cloud, automating their most expensive operations. Fully compliant, fully owned by them, with measurable ROI in weeks.

70%lower delivery cost; working software in four weeks

“They were reliable, they came up with a great solution, and their knowledge was unrivalled. One of the top delivery teams we have ever worked with. World class.”

Placeholder testimonial · Programme Director, Client Name

Your success story could be next.

Ambitious organisations choose Door Fifteen to deliver lasting business impact. Let's talk about yours.

Start a conversation
Contact

Open the door. Let's build something remarkable.

Tell us about your product, platform or AI ambitions and we'll come back within one working day with clear next steps, usually a free discovery session with our senior team.

Template note: wire this form to your CRM, email provider or form service before going live.

Offices

Proudly headquartered in England, working with clients everywhere.

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General enquiries
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