Advanced matching is a Meta Pixel feature that sends details a visitor has given you, such as an email address or phone number, to Meta in hashed form alongside a tracked event, so Meta can link that event to a Facebook or Instagram account. Better matching means more of your sales and leads are attributed to your ads, and Meta’s delivery system has more to learn from.
How advanced matching works
When someone buys, books or submits a form on your site, the Meta Pixel records an event. On its own, the pixel relies on cookies and browser signals to work out who that person is on Meta, and many visitors cannot be identified that way. Advanced matching adds customer information you already hold: email, phone number, first and last name, town, postcode and date of birth.
Before leaving the browser, each value goes through hashing with the SHA-256 algorithm, which turns an address like jane@example.co.uk into a fixed string of letters and numbers. Meta compares that string with hashes of its own users’ details and, where they match, connects the event to the account.
There are two forms:
- Automatic advanced matching is a switch in Events Manager. The pixel looks for recognisable fields, such as an email input, on pages where it fires, and sends hashed values without any code changes.
- Manual advanced matching means your developer passes specific values into the pixel code, such as the customer’s email on the order confirmation page. It is more precise, and you decide exactly what is sent.
The same customer details can also be sent from your server through the Conversions API, and Meta grades the overall result as Event Match Quality.
Why it matters for a UK business
Since Apple’s tracking changes and the spread of browser privacy features, more conversions slip through when matching relies on cookies alone. Advanced matching recovers some of them, so reported results sit closer to reality, Meta has more signal to optimise towards, and retargeting audiences grow.
It also brings legal duties. Hashed data is still personal data under UK GDPR, because Meta can link it to a person; hashing is pseudonymisation, not anonymisation. Under PECR the pixel itself needs consent before it runs, so advanced matching should only operate for visitors who accept marketing cookies in your banner. You need a lawful basis for sharing the data, and your privacy notice should say that hashed contact details are shared with Meta for advertising and measurement. The ICO’s guidance on cookies and similar technologies applies directly here.
Common mistakes
- Switching on automatic advanced matching without checking which forms the pixel can read, including forms that ask about health or finances.
- Letting the pixel, and its matching data, fire before the visitor has made a consent choice.
- Formatting phone numbers inconsistently in a manual set-up. Meta expects digits with the country code, so a UK mobile becomes 447 followed by the rest of the number, without the leading zero.
- Leaving the privacy notice silent about sharing data with Meta.
- Assuming advanced matching replaces the Conversions API, when the two work best together.
How to act on it
Open Events Manager, select your dataset, and check Event Match Quality for your purchase or lead event. Review the advanced matching settings and decide which fields you are comfortable sending; on most service and shop sites, email and phone at checkout or form submission do most of the work.
Confirm that your consent banner holds the pixel back until a visitor accepts, update the privacy notice, and on sensitive sites, such as private healthcare, use manual matching limited to pages you have chosen. Re-check Event Match Quality a week later. Tracking set up this way is part of the onboarding for my Facebook and Instagram ads management.