If you run a digital agency that builds custom software for clients, you have almost certainly wondered whether the work qualifies for R&D tax credits. And you have probably been told it doesn't, because the software belongs to the client, not you.
That advice is half-right and half-wrong. And the wrong half could be costing your agency tens of thousands of pounds.
Here is the truth: R&D tax credits for custom software built for client projects are absolutely claimable, provided the work meets HMRC's definition of qualifying R&D. The ownership of the intellectual property is not the deciding factor. What matters is whether the project involved resolving technical uncertainty that a competent professional in the field could not readily overcome.
This article explains exactly where the line sits, what HMRC looks for, and how to structure a claim that survives scrutiny. We work exclusively with agency founders, and we see too many agencies leave this money on the table because of a misunderstanding that is now costing them real cash.
What HMRC Actually Means by R&D
Let's start with the statutory test. Under the Corporation Tax Act 2009, qualifying R&D exists when a project seeks to achieve an advance in science or technology by resolving scientific or technical uncertainty that is not readily deducible by a competent professional in the field.
Three conditions must all be met:
- An advance in science or technology overall, not just for your business or client
- Technical uncertainty that could not be resolved by a competent professional working in the field
- A project that attempted to resolve that uncertainty, whether or not it succeeded
Notice what is not in that list. There is no requirement that you own the resulting IP. There is no requirement that the work was speculative rather than client-funded. There is no requirement that the project was internal rather than commercial.
The question is purely technical: did you attempt to solve something that no competent developer could have solved with existing knowledge?
Where Most Agencies Get It Wrong
The most common objection we hear from agency founders goes like this: "We just built a standard CRM for a client. There was nothing innovative about it. We used React, Node.js, and a PostgreSQL database. That's not R&D."
And that is correct. Building a standard CRM using well-understood tools and established patterns is not R&D. You did not resolve technical uncertainty. You applied existing knowledge competently. That is good work, but it is not claimable.
But here is where the same founder often misses the real opportunity. Within that same project, the client asked for a module that could process real-time video feeds from 200 simultaneous sources, extract facial expressions, and generate sentiment analysis within 200 milliseconds. The standard libraries could not handle that load. The existing documentation was contradictory. The team spent six weeks iterating on data pipeline architectures, testing different compression algorithms, and building a custom caching layer that did not exist before.
That six weeks is R&D. The rest of the CRM build is not. And the fact that the client paid for the entire project does not disqualify the R&D element.
HMRC's own guidance is clear on this. The CIRD81900 manual states that work can qualify regardless of whether it is funded by a client, as long as the technical uncertainty exists and the advance is genuine.
The IP Ownership Myth
There is a persistent belief that R&D tax credits require the claimant company to own the intellectual property generated by the project. This is not correct for the SME R&D tax credit scheme.
Under the SME scheme, the claimant must be the company that carried out the R&D. That company must also bear the financial risk of the R&D expenditure. But "bearing the financial risk" does not mean you cannot charge the client for the work. It means you must be the entity that pays for the staff time, subcontractors, and materials involved in the R&D activity.
In practice, this works perfectly well for most agency-client relationships. Your agency employs the developers, pays their salaries, covers the software licences, and invoices the client for the completed work. You bear the cost of the R&D activity. The client pays for the outcome.
Where it gets complicated is if the contract transfers the financial risk to the client through a cost-plus arrangement or a time-and-materials agreement where the client reimburses your costs directly. In those cases, the risk may sit with the client, and the claim would belong to them, not you. But for a standard fixed-price or milestone-based project, the risk sits with you, and the claim is yours to make.
What Qualifies as Technical Uncertainty in Software
This is the practical question that determines whether your claim will succeed or fail. HMRC does not accept "we built something new for our client" as sufficient. The advance must be in the underlying science or technology, not just in the application of existing technology to a new commercial context.
Examples that typically qualify for R&D tax credits custom software agency claims:
- Developing a novel algorithm to process unstructured data at scale where existing libraries could not handle the volume or accuracy requirements
- Building a real-time rendering engine for 3D visualisations where off-the-shelf solutions produced unacceptable latency
- Creating a custom machine learning model that required adapting fundamental approaches because standard architectures failed on the specific data set
- Designing a distributed system architecture to handle 10x the throughput of any existing reference implementation, requiring novel approaches to data sharding and consistency
- Developing a custom compression algorithm for high-resolution medical imaging where existing standards produced unacceptable quality loss
Examples that do not qualify:
- Building a standard e-commerce website using Shopify or WooCommerce, even with heavy customisation
- Integrating third-party APIs using their documented methods
- Applying standard design patterns to build a mobile app
- Migrating a database from one platform to another using standard tools
- Building a website with a custom CMS where the underlying technology choices are well-established
The line can be fine. A project that looks like routine development on the surface may contain genuine R&D activity underneath. The key is to identify the specific technical uncertainties that your team faced and the work they did to resolve them.
How to Structure Your Claim
If you have identified qualifying R&D activity within client projects, the next step is to prepare your claim properly. HMRC has become significantly more rigorous in recent years. Claims that lack technical justification or are supported by vague descriptions are being rejected at increasing rates.