Full Answer

Event Match Quality answers a single question for Meta: given the customer parameters you sent with an event, how confidently can we tie it to a person? It's scored 1 to 10 per event type, and it directly affects how well your conversions feed optimisation and attribution. Scores drifting below about 6 mean Meta is matching fewer of your purchases, which starves bidding and undercounts results.

The score rises with the quantity and accuracy of identifying parameters. Meta's Conversions API accepts hashed email, phone, first and last name, city, state, zip, country, and external ID, plus the fbp browser-id cookie and the fbc click-id cookie. The more of these you send correctly, normalised and SHA-256 hashed to spec, the stronger the match. Common EMQ killers are missing phone or address, unhashed or wrongly formatted fields, and dropping fbc because the click identifier expired.

This is where server-side capture earns its place. At the WooCommerce order hook your server already holds verified email, phone, and billing address, the exact fields that raise EMQ, and it can send them even when the browser pixel was blocked or consent limited client-side firing. Pixel-only setups tend to plateau low precisely because the browser never had clean customer data to begin with. Send richer events from the server and EMQ follows.