Custom app development means building a mobile or web app around how your business actually works: the engineer’s job sheet, the customer’s reorder, the warehouse count. We build business apps for UK firms, publish what they cost, and assign every line of the code to you.
Most of the app market is consumer apps: games, social, retail. That is not what we build. We build the apps that run operations: the ones a field engineer opens forty times a day, a trade customer uses to reorder without phoning, or a site manager uses to log a delivery in the rain.
That kind of app lives or dies on three things consumer apps barely care about: working without signal, connecting properly to the systems you already run, and being fast enough that people prefer it to paper.
What a business app actually is
A business app is software your staff or customers carry with them, built around one job they do repeatedly.
Field-team apps. Engineers, drivers, surveyors and inspectors capture job details, photos, signatures, parts used and time on site, then sync to the office system. No retyping job sheets at the end of the day.
Customer self-service apps. Trade customers check stock, see their account pricing, reorder and track deliveries without calling your sales office.
Internal operations apps. Stock counts with a barcode scanner, goods-in checks, maintenance rounds, safety inspections and approvals that currently live on clipboards and in WhatsApp groups.
Companion apps to a system you already have. A mobile front end on your ERP, CRM or job management system that does the three things people actually need on the move, rather than the 300 things the desktop product does.
The common thread is that each one replaces paper, phone calls or retyping, and that saving can be measured in hours before anything is built.
Why custom beats an off-the-shelf app
Off-the-shelf field-service and inspection apps are good products. They are also built for the average of thousands of businesses, priced per user per month for ever, and they stop exactly where your process starts being different.
You stop paying per seat for ever. App subscriptions are almost always per user, and the user count only goes one way as you grow. Five years of seats is usually more than the build.
The app fits the job, not the other way round. If your engineers need to record batch numbers, take a photo of the meter and capture a customer signature in that order, the app should do exactly that in three taps. Generic apps make people work around them, and people who work around an app stop using it.
It connects to your systems properly. A custom app writes straight into your job, stock or accounting system. A generic one usually means an export, a Zapier chain, or someone retyping the day’s jobs at 5pm.
It works where your people work. Offline-first design, built for cellars, plant rooms and rural sites, is a decision you make at the start of a custom build. In a generic app it is whatever the vendor decided.
You own it. No vendor repricing, no feature you depend on being retired, no data held in someone else’s platform. All IP assigns to you on final payment.
The five-year arithmetic
The number that settles most build-or-buy conversations. This example is a field team, with the assumptions stated so you can rerun it with your own figures.
Assumptions: 60 field users. A field-service app at £45 per user per month. A custom app at £55,000 to build, plus £6,000 a year for OS updates, hosting and small changes (about 11% of the build cost per year).
| Year | Per-seat app (cumulative) | Custom app (cumulative) |
|---|---|---|
| 1 | £32,400 | £61,000 |
| 2 | £64,800 | £67,000 |
| 3 | £97,200 | £73,000 |
| 4 | £129,600 | £79,000 |
| 5 | £162,000 | £85,000 |
Break-even falls at about two years and one month. By year five the custom app has cost £77,000 less, and it is an asset you own rather than a subscription you rent.
Where the arithmetic does not work: a team of ten users on the same subscription pays £27,000 over five years, which is less than the build. Below roughly twenty-five regular users, a custom app has to earn its keep through process fit and integration, not licence savings, so we run both calculations before recommending anything.
The hours saved usually matter more than the licences. Twenty engineers each spending 25 minutes a day retyping job sheets is 1,875 hours a year (at 225 working days). At a fully loaded £22 an hour, that is £41,250 a year in admin time, before counting the errors a retyped sheet introduces.
Native, cross-platform or web app?
The first technical decision, and the one most often made for the wrong reason. Four questions settle it.
| Progressive web app (PWA) | Cross-platform app | Native app | |
|---|---|---|---|
| What it is | A web app installed to the home screen | One codebase for iPhone and Android | Separate apps per platform |
| Typical use | Customer portals, simple internal tools | Most business apps | Heavy hardware or graphics use |
| Offline | Limited but workable | Strong | Strongest |
| Camera, GPS, barcode | Basic | Full | Full |
| App store needed | No | Yes, or private distribution | Yes, or private distribution |
| Relative cost | Lowest | Middle | Highest (two codebases) |
1. Does it need to work without signal? If staff work in basements, rural sites or plant rooms, you want a cross-platform or native app with proper offline storage and sync. A web app can cache a little; a real offline-first app is designed for it from the start.
2. Does it use the hardware heavily? Barcode scanning, Bluetooth printers, NFC tags, continuous GPS. Cross-platform handles nearly all of these. Native is only worth the second codebase for genuinely demanding hardware or graphics.
3. Who installs it? Customers will rarely install an app for a supplier they order from monthly; a PWA or plain web portal reaches them with no friction. Staff can be given an app through your device management, so installation is not a barrier.
4. How often will it change? A web app updates instantly for everyone. Store apps need a review and an update on each device. Fast-changing processes favour the web.
Our default for business apps is cross-platform, with a web portal sharing the same back end where customers are involved. One API serves both, so the logic is written once.
What we build
Field-service and job apps. Job lists, routes, checklists, photos, signatures, parts and time capture, offline sync, and a live link to your job or ERP system.
Inspection and compliance apps. Structured inspections with mandatory fields, photo evidence, timestamps and location, producing an audit trail that stands up to scrutiny.
Warehouse and stock apps. Barcode-driven goods-in, picking, counts and transfers on rugged devices or ordinary phones, writing directly into your stock system.
Customer and trade apps. Account pricing, stock availability, reordering, delivery tracking, documents and invoices, often paired with a web portal on the same back end.
Internal workflow apps. Approvals, requests, holiday and expenses, incident reporting: the things currently run through email chains and spreadsheets.
Mobile front ends on existing systems. The three tasks people need on the move, built against the API of a system you already own, instead of the vendor’s generic mobile app.
What custom app development costs in the UK
Published, like every other price on this site.
| Scope | Typical range | Duration |
|---|---|---|
| Discovery & app scoping | £3,000 – £8,000 | 1–2 weeks |
| Progressive web app over an existing system | £12,000 – £35,000 | 6–12 weeks |
| Cross-platform app, one user type | £20,000 – £50,000 | 8–16 weeks |
| Cross-platform app + customer web portal, shared back end | £45,000 – £120,000 | 14–26 weeks |
| Offline-first field app, multiple roles + integrations | £50,000 – £120,000 | 16–28 weeks |
| Support and OS-update retainer | From £800/month | Ongoing |
Our minimum build engagement is £10,000. Discovery sits below it on purpose, so you can scope the app properly before committing to the build.
What moves the price most: integrations with systems you do not control, offline sync (designing what happens when two people edit the same job without signal is real work), and the number of user types. The screen count matters far less than most people expect.
Running costs to budget for: the Apple Developer Program costs US$99 a year (charged in local currency) and a Google Play developer account is a one-off US$25 registration. Hosting for a typical business app back end runs £20–£200 a month depending on usage.
Getting the app onto phones
Business apps rarely need to be public, and keeping them private is simpler than most people assume.
Internal apps can be distributed privately: through Apple Business Manager as a custom app for iPhones, and through managed Google Play for Android devices, usually alongside your device management. Your app never appears in a public store search, and only your organisation can install it.
Customer apps go through the public App Store and Google Play, each with its own review. We handle submission, store listings and the review process, under your developer accounts, so the listing belongs to you.
Store commission is not usually an issue for business apps. Apple and Google take a commission on digital goods and subscriptions sold inside an app. Apps that sell physical goods, take orders on account, or are provided free to your staff and customers generally fall outside it, but check your model at discovery rather than assuming.
The cost nobody quotes: keeping it current
Every app needs work after launch even when nothing about your business changes, because the platforms change underneath it.
Apple and Google each ship a major OS release every year. Google Play also requires apps to target a recent Android API level to keep publishing updates. An app nobody touches for two years eventually stops installing on new phones or gets blocked from updates.
Budget roughly 10–20% of the build cost per year for OS updates, dependency updates and small changes. That is the honest running cost of any app, custom or not; with a subscription it is simply built into the per-seat price.
This is why we hand over the build pipeline, not just the code. The automated build and signing setup lives in your accounts, so any competent mobile developer can ship the annual update without us.
How we work, week by week
Week 0. A free 45-minute call. What the job costs you now in hours, retyping and errors, what an app would be worth, and the honest range.
Weeks 1–2. Discovery. We ride along: shadow the engineer, stand in the warehouse, sit with the customer service team. We map the exact sequence of the job, test every integration against your real systems, and decide platform and offline approach with you. You get a costed plan that is yours to keep, including the right to take it to another supplier.
Build, in two-week stages. A working app on real phones from the first stage, tested by the people who will use it. Not screenshots, not a demo: the app, on their phone, doing their job.
Pilot. A small group uses it for real for two to four weeks before full rollout. This is where we find the button that is too small for a gloved hand.
Handover. Source code, build pipeline, store listings, developer accounts and back end infrastructure, all in your name. All IP assigns to you on final payment.
Risks, and how each one is handled
Nobody uses it. The most common way business apps fail. Handled by building with the people who will use it from week one, measuring adoption in the pilot, and treating “slower than paper” as a defect.
Offline sync conflicts. Two people edit the same record without signal. Handled by designing the conflict rules in discovery, in plain English, with you, before any code exists.
The integration is harder than promised. Handled by connecting to your real systems during discovery, authenticating and pulling real records, not trusting that “they have an API”.
The app is abandoned after launch. Handled by handing over the build pipeline and documentation, so you are never dependent on us for the annual OS update.
Store rejection. Handled by building to Apple and Google review guidelines from the start and using private distribution where the app is internal.
Who this is for
Good fit: UK businesses with a team doing the same job repeatedly away from a desk, or customers who would rather self-serve than phone. Typically 10–250 staff, often in field services, wholesale and distribution, construction and trades, logistics, facilities management and healthcare administration. Build budget from £10,000.
Not a good fit: consumer apps aimed at the general public, games, social apps, or anything whose business model depends on going viral. Those need a specialist consumer studio and a marketing budget, not a business software firm.
Frequently asked questions
How much does it cost to build an app in the UK?
A business app typically costs £20,000 to £50,000 for a cross-platform app with one type of user, and £50,000 to £120,000 for an offline-first field app with several roles and integrations. A progressive web app over an existing system starts from £12,000. Discovery is £3,000 to £8,000.
How long does app development take?
Eight to sixteen weeks for a focused cross-platform app, and sixteen to twenty-eight weeks for a larger field app with offline sync and integrations. Discovery takes one to two weeks first.
Should we build for iPhone or Android?
Usually both, from one cross-platform codebase, which costs far less than two native apps. Native is only worth it for demanding hardware or graphics work.
Do we need to put the app in the App Store?
Not for internal apps. They can be distributed privately through Apple Business Manager and managed Google Play. Customer-facing apps normally go through the public stores, under your own developer accounts.
Can the app work without signal?
Yes, if it is designed for it from the start. Offline-first apps store data on the phone and sync when signal returns, with agreed rules for conflicting edits.
Can it connect to our existing systems?
Usually. Most of our apps write into an ERP, job management, stock or accounting system. We test each integration during discovery against your real data before quoting the build.
Do we own the app?
Yes. All IP assigns to you on final payment: source code, build pipeline, store listings and back end infrastructure, all in your accounts.
What does an app cost to run after launch?
Budget roughly 10–20% of the build cost per year for OS updates and small changes, plus hosting of around £20–£200 a month and the US$99 yearly Apple Developer Program fee. A support retainer starts from £800 a month if you want us to handle it.
Is a custom app cheaper than a subscription app?
Over five years, usually yes once you have more than about twenty-five regular users. Below that, a custom app needs to justify itself on process fit and integration rather than licence savings, and we will show you both calculations.
Can you build a web portal and an app together?
Yes, and it is often the best architecture: one back end and API serving both, so the business logic is written once and stays consistent.
Next step
A 45-minute call, free, no proposal attached. Bring the job your team does most often; we will work out together what it costs you today and what an app would be worth.
Written by Jas Singh, Founder. Last updated 8 October 2026. Licence comparison uses illustrative per-seat pricing stated in the table; rerun it with your own figures. App store fees as published by Apple and Google at the time of writing.
