UK VAT numbers used to be validated through VIES like every other European country. After Brexit they moved to HMRC's own API, which is well-designed for what it does, but comes with some integration overhead that's worth knowing about upfront.
I had customers all over the world, storing thousands of VAT numbers in our SaaS solution, and sometimes a mess, manually managed. That brought me to finding a better way to validate them.
Here's a clean way to handle UK VAT validation, and how to extend it to cover EU and beyond with the same integration.
The HMRC API is solid, but not lightweight
HMRC's VAT validation endpoint lives inside their MTD ("Making Tax Digital") API platform. It's a proper, well-documented API. But it's built for accountancy software integrations, not quick checkout validations. Using it directly means:
