Web & mobile application development

Application Development for Web, iOS and Android

Product apps with accounts, payments, notifications and an admin panel behind them — designed, built and released to the App Store and Google Play by one team working UK business hours.

  • Cross-platform or native, chosen on evidence
  • Store submission and review handled for you
  • App, backend and admin panel from one team

Why app projects slip

Most app projects struggle below the surface.

The screens are the visible part. Accounts, payments, notifications, offline behaviour, admin tools and app store rules sit underneath — and that is where budgets and timelines usually go.

What a good first release includes

A first version people keep using usually needs fewer features and more of the unglamorous essentials:

  • Sign-up, login and in-app account deletion
  • Payments that follow App Store and Google Play rules
  • Push notifications people have opted into
  • An admin panel for support, content and refunds
  • Crash reporting and product analytics from day one

The wrong platform choice

Native where cross-platform would do doubles the build and the upkeep. Cross-platform where the app leans on Bluetooth, background work or heavy graphics turns every sprint into a fight with the framework.

Rejected at app store review

Payments that break store rules, missing privacy details, no way to delete an account inside the app, crashes on older devices — late surprises that push the launch date back.

No way to run the business behind it

The app ships, but support staff cannot look up a customer, refund an order or change content without a developer running database queries for them.

Works in the office, fails on the train

Patchy signal, expired sessions and slow APIs were never tested, so real users meet endless spinners, lost form data and the occasional double payment.

How we work

From first sketch to the app stores.

Seven stages, with app-specific work inside each: a platform decision made on evidence, store rules checked before design, and test builds on your own phone from the early sprints.

  1. 01

    Discovery

    We define who the app is for, what it must do on day one, and what it depends on — payments, device hardware, existing systems, offline use — because those decide the platform.

    Core journeys and technical constraints

  2. 02

    Strategy

    Cross-platform or native, app or web app, and what goes into version one: we make the call with you, in writing, with the cost and trade-offs of each option.

    Platform decision and first-release scope

  3. 03

    UX & architecture

    Clickable prototypes tried on real phones, following iOS and Android conventions where users expect them, alongside the API design and data model for the backend.

    Tested prototype and API design

  4. 04

    Development

    Two-week sprints with a demo each time, and test builds installed on your own phone through TestFlight and Google Play testing tracks, so feedback arrives while it is cheap to act on.

    Installable test builds every sprint

  5. 05

    Testing

    Automated tests plus manual checks on a spread of real iOS and Android devices and OS versions, poor-network scenarios, accessibility and a payment test plan.

    Device test matrix and release sign-off

  6. 06

    Launch

    Store listings, privacy details and review submissions handled for you, then a phased rollout so any problem surfaces with a small group of users first.

    Live on the App Store and Google Play

  7. 07

    Optimisation & support

    Crash and usage monitoring, updates for each new iOS and Android release, and a roadmap shaped by what people actually do in the app.

    OS updates covered and a feature roadmap

Technology

The stack our apps are built on.

We choose per project and explain the choice. Most product apps start cross-platform; native is there when the app genuinely needs it.

Cross-platform

React NativeFlutterIonicTypeScript

Native

Swift for iOSKotlin for AndroidPlatform SDKsWidgets and extensions

Web apps

ReactNext.jsVueProgressive web apps

Backend

Node.jsPythonPostgreSQLFirebase

Payments and messaging

StripeIn-app purchasesPush notificationsWebRTC video calls

Release and quality

TestFlight and Play testing tracksAutomated UI testsCrash reportingGitHub Actions builds

Some products do not need an app at all — a well-built web app can be cheaper to run and quicker to update. If that is you, we will say so before you pay for two store listings.

Use cases

What UK product teams build with us.

Different products, the same essentials underneath: accounts, payments, notifications, an admin panel and a release process that does not depend on one person.

Startups and founders

A first customer app

A focused iOS, Android and web product with sign-up, payments and an admin panel — enough to launch, charge and learn from real users.

Service businesses

Bookings and appointments

Availability, bookings, reminders, deposits and cancellations synced with staff calendars, so the front desk stops managing the diary by phone.

Field and operations teams

An offline field app

Inspections, deliveries or site visits recorded on a phone with photos and signatures, working without signal and syncing once back in coverage.

Retail and hospitality

Ordering and loyalty

Order-ahead, rewards and personalised offers, connected to the till, booking or eCommerce system you already use.

Health and wellbeing

Tracking and coaching

Logging, progress charts, reminders and coach messaging, with personal and health data kept to what the app needs and handled in line with UK GDPR.

Established businesses

Rebuilding an ageing app

An app with poor reviews, crashes on new OS versions or an unsupported stack, rebuilt with existing users, data and store listings carried across.

Why Techsleight

What working with us is actually like.

No inflated numbers — just how we run projects, and what you can hold us to.

Product engineering, not ticket-taking

We ask what the software is for before we estimate it — and we will tell you when something should not be built, or should be bought instead.

AI where it earns its place

LLM features, retrieval and automation built with evaluation, guardrails and cost controls, and plain software where that is the better answer.

Full-stack under one roof

Design, frontend, backend, mobile, cloud and QA in one team, so nothing falls between suppliers.

UK-focused delivery

UK business hours, estimates in pounds, and a contract with a UK company. Our engineers are based in the UK and India.

Flexible engagement

A fixed-scope project, dedicated developers or a monthly retainer — and you can move between them as the work changes.

You own everything

Code, IP, cloud accounts and documentation are yours from day one. We sign an NDA before discovery if you need one.

Support after launch

We stay on for fixes, upgrades and new features, or hand over cleanly to your in-house team with the documentation to match.

FAQs

Questions we get asked.

Straight answers on scope, cost, timelines and how we work. If yours is not here, ask us directly.

Ask us a question

How much does it cost to build an app in the UK?

Cost is driven by the platforms, the backend and the integrations far more than by the number of screens. A discovery sprint from £2,000 produces a prototype, a platform recommendation and a fixed-price quote for the first release. Ongoing development can then run with dedicated developers from £2,900 a month.

Should we build native or cross-platform?

For most product apps — accounts, content, payments, messaging — React Native or Flutter give one codebase for iOS and Android with a native feel, at lower cost. Native Swift and Kotlin make sense when the app depends heavily on device hardware, background work or demanding graphics. We make the call with you in discovery and write down why.

Do we need a mobile app, or would a web app do?

If people use the product occasionally, find you through search or work at a desk, a web app is often the better first step: no store review, instant updates, one codebase. An app earns its place with frequent use, push notifications, offline use or device features such as the camera, location or Bluetooth.

How long does it take to build an app?

We work in two-week sprints, with installable test builds from early on. A focused first release is typically planned over weeks, not months — an MVP is often in the region of 6–10 weeks — with time for app store review built into the plan. You get a dated plan after discovery.

Can we take payments inside the app?

Yes, but the method depends on what you sell. Physical goods and real-world services can usually be paid for with Stripe, Apple Pay or Google Pay. Digital content and subscriptions used inside the app generally have to go through Apple’s and Google’s in-app purchase systems. Store rules change, so we check them against your model before designing the checkout.

Will you publish the app to the App Store and Google Play?

Yes. We prepare the listings, screenshots, privacy details and review notes, and submit under your own developer accounts so the apps belong to your business from the start. If a reviewer raises questions, we handle the response and the resubmission.

Can the app work offline?

Yes, when it is designed for it from the start. We store data on the device, queue changes made without signal and sync them when the connection returns, with clear rules for when two people edit the same record. Adding offline support later is much harder, which is why we ask about it in discovery.

How do you handle personal data and UK GDPR?

We collect only what the app needs, encrypt data in transit and at rest, keep secrets out of the app bundle, and build consent, data export and account deletion into the product. We can supply technical detail for your privacy notice and DPIA; sign-off stays with you.

Who owns the app, the code and the store listings?

You do. Source code, designs, store listings, developer accounts and cloud accounts are all set up under your organisation from the start. There is no ongoing licence fee to keep using what we built.

What happens after launch?

Apple and Google ship major OS releases every year, and store policies change more often than that. Support covers OS updates, crash fixes and dependency upgrades, plus a feature roadmap based on real usage — or a documented handover to your own developers.

Start a project

Planning a web or mobile app?

Tell us who it is for and what it has to do on day one. We will come back with questions, a view on platform, and what a sensible first release would include.

  1. 1A senior engineer reads your brief within one working day, and replies with questions or a first view.
  2. 2A 30-minute call to understand the goal, constraints and what good looks like — no sales script.
  3. 3A written proposal with scope, milestones, team and a GBP estimate you can take to your board.

Techsleight Labs is a trading name of Krapton IT Consultancy.

Reply within one working day. NDA on request. Your details are used only to respond — privacy policy.