Who owns the code when an agency builds your app?

Unless your contract says otherwise, the agency owns the code it writes for you. Under UK copyright law the author of a work is its first owner, and paying the invoice does not change that. To own your app outright you need a written assignment of copyright, signed by the agency, that covers the code, the designs and everything else made for the project. Agree it before the build starts, not after launch.

Who owns the copyright in code an agency writes?

The person or business that writes the code owns the copyright in it, unless an exception or a signed transfer applies. Software counts as a literary work under the Copyright, Designs and Patents Act 1988, which lists "a computer program" in its definition of literary works . That means app code gets the same protection as a book.

The Act's starting rule is short: "The author of a work is the first owner of any copyright in it" . The main exception is employment. When an employee writes code as part of their job, the employer is the first owner.

An agency, a freelancer or a contractor is not your employee. So the code they write for your app belongs to them by default, even though you came up with the idea, wrote the brief and paid for every hour.

Why does paying for the build not make you the owner?

Paying for software buys you the work, not the copyright in it. As the UK legal service Sprintlaw puts it, paying a contractor or agency to create software "does not automatically mean your company owns the copyright in the code" .

The law is strict about how ownership moves. Section 90 of the Act says "An assignment of copyright is not effective unless it is in writing signed by or on behalf of the assignor" . The assignor is the agency, so the agency's signature is the one that matters. An email saying "it's all yours", a verbal promise on a call or a line in a proposal nobody signed will not do it.

In practice a court would usually find you have an implied licence to use what you paid for. That sounds reassuring until you want to sell the business, raise investment, move to a new developer or stop a former supplier reusing your code for a competitor. Buyers and investors check this during due diligence, and a vague implied licence rarely satisfies them.

What is the difference between an assignment and a licence?

An assignment transfers ownership of the copyright to you, while a licence only gives you permission to use something the agency still owns. Both are legitimate, and most app contracts use a mix of the two.

• Assignment. You own the code outright. You can change it, hire anyone to work on it, sell it with the business and stop others copying it.
• Exclusive licence. The agency keeps ownership, but only you may use the work in the agreed way. Section 90 also requires this in writing to be fully effective against others.
• Non exclusive licence. You may use the work, and so may the agency and anyone else they choose to license it to.

A licence is normal for things the agency already owned before your project, such as a login module or a component library it reuses for every client. Sprintlaw suggests asking for a perpetual, worldwide, royalty free licence for those, so you can keep using, changing and supporting them even if you part ways. The bespoke parts of your app, the bits nobody else has, are what the assignment should cover.

What should the contract say before you pay a deposit?

The contract should assign every piece of work made for your project to you, in writing, signed by the agency. Get this agreed before the first payment, because that is when you have the most leverage. Look for these points:

1. A clear assignment clause. All intellectual property created for the project passes to you. Say when it passes: on signature, on creation, or on full payment. Assignment on full payment is common and fair, as long as the trigger is stated.
2. A broad definition of the work. Source code, compiled apps, database structure, designs, icons, copy, documentation and test scripts. Leaving out the designs is a common gap.
3. Background IP and its licence. A list of anything the agency already owned and is reusing, with the licence terms described above.
4. Open source disclosure. Nearly every app uses free open source libraries. Some licences only require a credit, while others can require you to publish your own source code if you distribute the app. Ask for a list of components and their licences.
5. Moral rights waiver. Authors have personal rights such as being credited. Contracts normally ask developers to waive these so you can change the code freely.
6. Subcontractors. If the agency uses freelancers, the agency must hold assignments from them too, otherwise it cannot pass on rights it never had.
7. Handover. Access to the code repository, the app store accounts in your name, hosting credentials and enough documentation for another developer to pick the project up.

None of this needs to be hostile. A good agency will have answers ready and will not flinch when you ask. If one refuses to assign the bespoke code at all, that tells you something about how hard it would be to leave later.

How AI written code complicates ownership

AI coding tools are now part of normal development, and that raises a new question about whether every line of your app is protected by copyright at all. The Stack Overflow 2025 Developer Survey found 84% of respondents were using or planning to use AI tools in their development process, and 51% of professional developers used them every day.

The UK is unusual here. Since 1988 it has protected "computer generated" works that have no human author. For those, section 9(3) treats the author as the person who made the arrangements for the work to be created, and section 12 gives them 50 years of protection rather than the usual life of the author plus 70.

That may change. The government's Report on copyright and artificial intelligence , published on 18 March 2026, proposes that this protection "should be removed" in the absence of evidence of its ongoing value. It notes that 78% of online survey respondents who answered the question were against keeping it. The same report says copyright should continue to protect works created with AI assistance. No date for new legislation has been set.

For a business commissioning an app, the practical points are:

• Code written with AI help, reviewed and shaped by a developer, is still likely to be protected as a human work, and the assignment clause handles it like any other code.
• Code produced wholly by AI with little human input could lose protection if the proposal becomes law. You would still be free to use it, but you might not be able to stop someone copying it.
• Your contract should cover it either way. Ask the agency to confirm how it uses AI tools, that a person reviews everything that ships, and that the assignment covers all project output however it was produced.

What if your app is already built without an assignment?

If your app was built without a written assignment, the fix is usually simple: ask the agency to sign a short confirmatory assignment now. Most agencies on good terms will sign one, sometimes for a nominal fee. It should name the project, list what is being assigned and be signed on behalf of the agency.

Do this before you need it. Fixing ownership in the middle of a sale, a funding round or a falling out with your old developer is slower and more expensive. While you are at it, check that the app store accounts, domain names and hosting are registered to your business rather than to the agency or a freelancer.

At KerenLabs we design and build web apps and mobile apps , and we are happy to explain exactly what you will own before any work starts. If you are weighing up a build or untangling an old one, book a free 15 minute call and we will tell you straight.

Frequently asked questions

Does a freelancer own the code they write for my business?

Yes, by default a freelancer owns the copyright in code they write, because they are not your employee. Ownership only passes to you through an assignment in writing signed by the freelancer. The same rule applies to agencies and other contractors.

Is an email enough to transfer copyright in the UK?

Usually not on its own. Section 90 of the Copyright, Designs and Patents Act 1988 requires an assignment to be in writing and signed by or on behalf of the person transferring it. A properly signed document, including a valid electronic signature, is the safe route.

Who owns the app store listing for my app?

Whoever owns the developer account the app is published under controls the listing. Ask for the app to be published under an Apple and Google developer account registered to your business. Moving an app between accounts later is possible but adds work and delay.

Can an agency reuse code from my app for other clients?

An agency can reuse its own background code, such as general tools and libraries it brought to the project, unless your contract says otherwise. Code written specifically for you should be assigned to you, which stops it being reused without your permission. Spell out which is which in the contract.