Mobile Application Development — Mobile App Development UK by Celsius Software

Systems

Mobile Apps That Connect to the Rest of Your Business

iOS and Android apps built to talk to your existing systems, not sit prettily on their own doing nothing useful.

A mobile app that doesn't connect to anything is a glorified brochure with a battery drain. We build mobile applications for iOS and Android that integrate directly with your existing CRM, ERP, stock or booking systems, so field staff, customers or engineers get real-time, accurate data on their phone rather than yesterday's export. Built around your actual workflow, tested properly, and maintained afterwards, because an app that stops working after the first OS update is worse than no app at all.

Features and benefits

What you get

Native and cross-platform builds — Mobile Application Development

Native and cross-platform builds

iOS and Android apps built to suit your users, budget and timeline.

Real-time system integration — Mobile Application Development

Real-time system integration

Apps connect directly to your CRM, ERP or other systems for live, accurate data.

Offline functionality — Mobile Application Development

Offline functionality

Field staff can keep working without signal, syncing data once reconnected.

Secure authentication — Mobile Application Development

Secure authentication

Proper login security and GDPR-conscious handling of user and business data.

Push notifications and alerts — Mobile Application Development

Push notifications and alerts

Real-time updates that actually matter, not notification spam.

Ongoing maintenance and updates — Mobile Application Development

Ongoing maintenance and updates

Apps kept current with OS updates, so it doesn't quietly stop working one Tuesday.

Expert insight

Why the app store submission is the easy part

Getting an app onto the App Store or Google Play is the easy, well-documented bit. The hard part — the bit most cheap app builds skip — is making sure that app connects properly and securely to the systems that hold your actual business data.

We build the integration layer with the same care as the app itself, so field staff, engineers or customers see live, accurate information rather than a snapshot from last week's data export. That's the difference between an app that gets used daily and one that gets deleted within a month.

We also don't disappear after launch. Operating systems update constantly, and an app that isn't maintained will eventually break — usually at the worst possible moment. Ongoing support keeps it working quietly in the background.

How we do it

Six steps to implementation

  1. 01

    Requirements and user research

    We find out who'll use the app, and what they actually need it to do.

  2. 02

    Integration and architecture design

    Connections to existing systems planned before design work begins.

  3. 03

    UI/UX design

    Designed for the people using it, not for an awards submission.

  4. 04

    Build and integration

    App and back-end integration built and tested together, not bolted on at the end.

  5. 05

    Testing and app store submission

    Thorough testing across devices, then submission and approval handled for you.

  6. 06

    Maintenance and support

    Ongoing UK-based support and updates to keep the app working as OS versions change.

25+

Years building business software

iOS & Android

Platforms supported

UK-wide

Clients supported

Questions

Frequently asked

Do you build for both iOS and Android?+

Yes, our mobile app development covers both iOS and Android, and we’ll advise on native versus cross-platform depending on your requirements, timeline and budget. Native apps suit performance-heavy or device-specific features, while cross-platform can be more cost-effective for simpler tools. Either way, the app is built around what your business actually needs rather than a default choice.

Can the app connect to our existing systems?+

Yes, connecting to your existing CRM, ERP or other business systems is core to how we approach mobile app development. We build secure, documented integrations so field staff or customers get live, accurate data rather than a disconnected app. It means the app becomes part of your wider systems rather than a separate silo.

Does the app work without an internet connection?+

We can build offline functionality into your mobile app development project, letting users keep working without a connection and syncing data automatically once it’s restored. That’s particularly useful for field-based UK teams working in areas with patchy signal. Conflicts between offline and online changes are handled sensibly rather than causing data loss.

Who handles app store submission?+

We manage the App Store and Google Play submission process for you as part of mobile app development, handling the technical requirements, listings and review process. That saves you wrestling with platform-specific rules and rejection reasons. We also handle resubmissions if either store requests changes before approval.

What happens when a new OS version is released?+

Ongoing maintenance keeps your app compatible with new iOS and Android releases, which is essential given how often operating systems change. As part of mobile app development we monitor for breaking changes and update the app proactively rather than waiting for it to stop working. That keeps the app reliable without you having to track OS updates yourself.

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