If your agency builds custom Klaviyo flows for clients, you have probably wondered whether the development time qualifies for R&D tax credits. The short answer is: yes, it can. But only for specific types of work. And the line between qualifying R&D and routine development is sharper than most agency founders realise.
This article explains exactly where that line sits. We will walk through what HMRC actually looks for in a klaviyo custom flow r&d claim, what almost certainly does not qualify, and how to structure your records so you do not waste time on a claim that gets rejected.
What HMRC Considers R&D in Software Development
HMRC follows the Guidelines on the Meaning of Research and Development for Tax Purposes (the BEIS guidelines). For software work to qualify, the project must seek to achieve an advance in science or technology. That advance must be in the field of software engineering, not in the client's business processes.
In plain English: you need to have attempted something that a competent professional in your field would not know how to do at the start of the project. If the solution was obvious or already documented, it is not R&D.
For Klaviyo specifically, the test is whether your team had to resolve technical uncertainty. Did you need to create a novel integration, build a custom data pipeline that Klaviyo does not natively support, or develop a scoring algorithm that required genuine experimentation?
If you simply configured standard Klaviyo triggers, conditions, and actions, that is skilled work. But it is not R&D.
What Qualifies as a Klaviyo Custom Flow R&D Project
Let me give you a concrete example from a real claim we submitted for a digital agency based in Manchester's Northern Quarter. They had a client in the subscription box space. The client needed a flow that could predict churn risk based on 14 behavioural signals, then dynamically adjust email frequency, content type, and discount thresholds in real time.
Klaviyo does not natively support multi-variable predictive scoring with dynamic content branching based on real-time data ingestion from three separate APIs. The agency had to build a custom middleware layer in Node.js, write a scoring algorithm from scratch, and create a feedback loop that updated the model as new data came in. They tested 11 different approaches before one worked reliably at scale.
That is R&D. The team faced genuine technical uncertainty. They did not know at the outset whether the approach would work. They documented their hypotheses, their failed attempts, and the eventual solution. HMRC accepted the claim.
Other examples that can qualify:
- Building a custom attribution model that pulls data from Klaviyo, Google Ads, Facebook, and an offline sales CRM, then reconciles them into a single customer view. Standard Klaviyo attribution is limited. If you need to build a custom solution because no off-the-shelf tool exists, that is technical uncertainty.
- Developing a bespoke personalisation engine that uses machine learning to select product recommendations based on browsing behaviour, past purchases, and real-time inventory. Klaviyo's built-in product recommendations are rule-based. If you are building something genuinely adaptive, you may have a claim.
- Creating a custom A/B testing framework that runs multivariate tests across email, SMS, and push notifications simultaneously, with statistical significance calculations that update in real time. Klaviyo's native testing is limited to simple A/B splits.
What Does Not Qualify
Most Klaviyo work falls into the "skilled but not R&D" category. That is fine. It does not make the work less valuable to your clients. It just means you cannot claim tax relief on it.
These activities almost never qualify:
- Setting up standard abandoned cart, welcome, or post-purchase flows. Even if you spend days perfecting the copy and design, that is marketing work, not technological advance.
- Segmenting audiences based on standard Klaviyo properties. That is configuration, not development.
- Integrating Klaviyo with Shopify, WooCommerce, or other standard platforms using existing connectors. If the integration is documented and supported, there is no technical uncertainty.
- Building email templates in Klaviyo's drag-and-drop editor. Even custom HTML templates are design work, not R&D.
- Any work that a competent Klaviyo developer could complete using publicly available documentation, forums, or standard practices.
The line is not always obvious. If you are unsure, ask yourself this: at the start of the project, did your senior developer say "I do not know if this will work"? If the answer is no, it is probably not R&D.
How the R&D Tax Credit Scheme Works for Agencies
For accounting periods beginning on or after 1 April 2024, the old separate SME and RDEC schemes were combined into a single merged R&D expenditure credit scheme. It gives a 20% taxable above-the-line credit on your qualifying expenditure, regardless of company size. Because the credit is itself taxable, the net benefit works out at roughly 15% of qualifying spend for an agency paying the 25% main rate of corporation tax, and around 16.2% for a loss-maker taxed at the 19% small-profits rate.
If your agency is loss-making, the merged-scheme credit can still be paid out as cash, subject to a PAYE and NIC cap. Loss-making SMEs that are R&D-intensive, meaning qualifying R&D is at least 30% of total expenditure, can instead claim under Enhanced R&D Intensive Support (ERIS). ERIS keeps the more generous route of an 86% enhanced deduction plus a 14.5% payable credit, worth up to around 27p for every £1 of qualifying spend.
For a profitable agency, every £100,000 of qualifying R&D spend generates a £20,000 credit under the merged scheme. After 25% corporation tax on that credit, the net benefit is around £15,000. That is real money that can fund more development or improve your bottom line.
Historically (for accounting periods beginning 1 April 2023 to 31 March 2024), most agencies claimed under the separate SME scheme, which gave a 186% enhanced deduction and a 10% payable credit for loss-makers. Those rules no longer apply to periods that begin on or after 1 April 2024.