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App development
App development means planning, designing, building and testing apps for phones, tablets or the web. You can start by making a small prototype and asking people to try it before deciding whether to build a complete app.
Open the interactive guide (checklist, video, read-aloud) →In plain words
- An app helps someone do a task on a phone or computer.
- Start with one small problem.
- Draw screens, then make a simple test version.
- Ask people to try it and share what is confusing.
- Improve it, check it, and agree costs before paid work.
Who it suits
It may suit patient beginners who enjoy solving problems, learning to code, or designing how an app works. Young beginners should involve a parent or guardian when discussing paid work, accounts or agreements with clients.
People pay for apps that solve a real problem or make a task easier. They may also pay for updates, fixes or new features, but demand and income are uncertain.
Step by step
- Choose one small problem to solve. Write down who the app is for and the one task it should help them complete. Keep the first idea narrow, such as tracking one routine rather than managing someone’s whole day. About 30-60 minutes.
- Ask potential users what they need. Ask a few people what they do now, what frustrates them and what a simple solution would need to do. Note repeated needs, rather than adding every suggestion as a feature. About 1-3 days.
- Sketch the main screens. Draw each screen on paper or use a design tool. Add arrows to show how someone moves between screens, and keep only the screens needed for the main task. About 1-3 hours.
- Make a prototype and ask for feedback. Create a clickable or working prototype before building the full app. Prototypes and user feedback are recommended ways to test and refine an app idea. Andy Maddock SAP About 1-7 days.
- Choose how you will build it. Pick an approach that fits your current skills: learn programming for more control, or explore low-code or no-code tools if you want to build visually. SAP About 1-3 days.
- Build the simplest useful version. Build only the features needed for the main task. Test the app on a phone or suitable test environment, and write down bugs or screens that are confusing. About Several days to several weeks.
- Watch people try the app. Ask people who might use it to try the prototype without coaching them. Notice where they pause or get stuck, listen to their comments, and use that feedback to improve the design. About 1-3 days.
- Test the changes and check safety. Test again after making changes, including reliability, security and compatibility with the devices you intend to support. Matrix Internet Check that the main task still works after each change. About 1-5 days.
- Agree the work or maintenance plan. For client work, agree what you will deliver, when you will deliver it, and how changes or ongoing support will be handled before starting. For your own app, decide how you will maintain it and respond to user feedback. About 1-2 hours.
Your first 15 minutes
Pick one small app idea, sketch its main screens, and ask three people who might use it to try the proposed user journey and give honest feedback.
The money
Estimate the time needed, include costs such as software or equipment, and agree the scope before work starts. Set out what is included, how extra changes are priced and whether later updates or support cost more; there is no reliable typical earnings figure.
Example only: In one week, two small prototype jobs at £40 each bring in £80; if costs are £10, £80 − £10 = £70 before tax. Separate example only: one small job at €60 with €8 costs leaves €52 before tax. These are illustrative figures, not recommended rates or an income forecast.
The rules
You do not need a general licence just to develop apps. No app-specific consumer or data-protection requirements are listed here. If you are a young beginner, ask a parent or guardian to help with accounts, paid work and client agreements.
UK and Northern Ireland
- Trading income and tax. The first £1,000 a year of your trading income is covered by the trading allowance. If your income is above that, tell HMRC. The allowance is based on your gross income before expenses. If you need to register for Self Assessment, do so by 5 October after the tax year ends. GOV.UK Tax Help for Hustles GOV.UK
- VAT. You must register for VAT if your taxable turnover is over £90,000. If you are unsure, check your position with HMRC. Business.gov.uk
- Personal data and ICO fee. The ICO fee guidance here covers the wholesale and retail sector. It does not say whether an app developer must pay a data protection fee. If you work in wholesale or retail, use the ICO's self-assessment tool to check whether you need to pay. The ICO says you are likely to be exempt if you hold customer details only for your own accounts and transaction records. This does not apply to information processed by or obtained from credit reference agencies. ICO
- Selling to consumers. No app-specific consumer information, cancellation or refund requirements are listed here.
- Licences, insurance and age. There is no general app-development licence or specific legal age identified for doing this work. Consider what insurance you may need. If you are young, ask a parent or guardian for advice before opening accounts or agreeing to paid client work.
Ireland
- Income tax reporting. If you work under PAYE, register for self-assessment using Form 11 if your taxable non-PAYE income is over €5,000 or your gross non-PAYE income is over €30,000. Below those limits, declare it on Form 12 through myAccount. Check your situation with Revenue or a tax adviser. Revenue
- VAT. The VAT thresholds are €42,500 for services and €85,000 for goods. If you are unsure which threshold applies to your activity, ask Revenue. Revenue
- Business name. If you trade under a business name other than your own, register it with the CRO. Online registration costs €20. CRO
- Data and consumer checks. No app-specific data-protection or consumer requirements or fees are listed here.
- Licences, insurance and age. There is no general app-development licence or specific legal age identified for doing this work. Consider what insurance you may need. If you are young, ask a parent or guardian before opening accounts or agreeing to paid client work.
Checked against official sources: 22 October 2026. Not yet reviewed by a qualified tax or legal adviser. General guidance, not legal advice. Check the official link beside each point before you start.
Common mistakes
- Building lots of features before checking that anyone needs the app.
- Making the first version too large instead of testing one main task.
- Skipping tests on different devices or after making changes.
- Ignoring security, personal data or accessibility while focusing only on features.
- Starting client work without agreeing what is included, when it is due and how changes are handled.
AI-made demonstration: this module has a 20-second street-chat video in the interactive guide. The presenter and the people in it are computer-generated, not real people.