Independent · AI-Native · Made in England

Great software, delivered with care. Built to last.

Door Fifteen is an independent software consultancy for ambitious organisations. We aim to design and engineer bespoke digital products that create meaningful value, backed by deep AI expertise we apply wherever it genuinely helps, with a commitment to leaving your teams stronger than we found them.

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AI-Native Delivery

Transforming businesses with intelligence.

We bring deep AI expertise to bear wherever it genuinely adds value, pairing it with subject matter expertise to help organisations drive new levels of efficiency. Our goal is to help your teams ship faster, with continuous improvement and scalable operations built in — applying AI judiciously, not for its own sake.

Custom AI designed for your business, deployed on your cloud and owned by you
Working software quickly, with a clear path to ROI
Agentic automation aimed at running your most expensive operations at a fraction of the cost
Citizen- and customer-centred AI, delivered responsibly in regulated environments

Fasttime from idea to launched product

Leantime to first working software

Efficientlower delivery cost with AI-augmented teams

Committedto earning every client's recommendation

Why Door Fifteen

Technology is our how. People are our why.

For ambitious enterprises and scale-ups: we combine experienced engineering, industry expertise and a people-centric mindset to harness technology for meaningful change. Our team's engineering experience spans some of the most technically demanding environments, and we aim to bring that same rigour to even the most challenging projects, with a minimum of fuss.

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Build the right thing, the right way

Human-centred product delivery from vision to launch: multidisciplinary teams aim to take you from idea to a digital product your customers love, quickly and without compromising on quality or safety.

🧭

Modernise with confidence

We transform legacy technology and simplify technical architecture, aiming to deliver fully-compliant solutions on time and within budget, with a focus on uptime and reliability.

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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.

“We aim to be the partner every client can rely on: collaborative, straightforward, and completely focused on real outcomes — delivered on time and within budget.”

— Door Fifteen

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 strategists, designers and engineers aim to 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 designed around what your customers actually want.

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

⚙️

Bespoke Software Engineering

Innovative, bespoke software engineered to create meaningful value, delivered by teams with deep technical experience who aim to handle even the most challenging builds with a minimum of fuss.

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

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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

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Mobile & Multi-Platform

Experts in everything mobile: transformational apps and connected experiences designed to 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 aim to ensure uptime and reliability with fully-compliant solutions and long-term support partnerships.

Legacy modernisation
Managed services & support
Quality engineering & testing

Technical depth

Deep experience with complex, engineering-led products.

Safety-Critical SystemsComplex Product EngineeringLegacy ModernisationEmbedded & Connected DevicesRegulated & Compliance-Heavy EnvironmentsMission-Critical Software

Not sure where to start?

Book a free discovery session and we'll help you identify the right problem to solve, and a fast, safe 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

Designed for fast value. Built to last.

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.

Deliver

Embedded, multidisciplinary squads aim to get you to working software quickly, and to a launched product soon after, shipping continuously without compromising quality or safety.

Scale

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

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-expert. Deep AI capability we apply where it adds real value, not bolted on for its own sake.
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: we aim for measurable results on every project. Work delivered on time and within budget, by engaged people who are committed to your satisfaction.

What we aim for

The value we aim to deliver, from day one.

Fasterdelivery, powered by AI-augmented engineering

Leanerengineering time on modernisation work

Lower costthan running expensive manual operations

Yoursall 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 Expertise

Digital products that matter, built around the people who use them.

We work at the heart of organisations, on the tough, complex challenges that get them closer to their customers. Here's the kind of work we take on — specific case studies will follow as projects complete.

What we take on

The kind of work we do.

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Modernising legacy platforms

Replacing ageing, business-critical systems with modern, maintainable platforms, without disrupting the operations that depend on them.

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Safety-critical software

Engineering software for environments where reliability isn't optional, and downtime or failure has real consequences.

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AI embedded in real operations

Applying AI where it genuinely reduces cost or effort, deployed on your infrastructure and owned by you.

🔌

Embedded & connected systems

Software that talks to hardware: connected devices, equipment, and the platforms that monitor and control them.

⚖️

Regulated, compliance-heavy delivery

Delivering technology that meets the standards your industry demands, without slowing your business down.

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Complex product engineering

Taking ambitious product visions from first idea to something real users depend on, however intricate the build.

“We want every client to say we were reliable, resourceful, and brought knowledge they could depend on — the kind of delivery team that's a genuine pleasure to work with.”