How it works
When something that matters happens, such as an order being paid, your backend sends an HTTPS request to Meta's Graph API with an access token, the event name and time, the page URL and customer details. Email addresses and phone numbers are normalised and hashed with SHA-256 before sending; the _fbp and _fbc cookie values, IP address and browser user agent go along unhashed to help matching. Events Manager grades the result with an Event Match Quality score.
Because it runs on your server, it also reports events a browser never sees: a payment confirmed later by a webhook, a phone order, an in-store sale or a lead that becomes a customer in your CRM. When the Pixel and the API both send the same event, giving both the same event name and event id lets Meta keep one copy, as long as they arrive within 48 hours of each other.
Setup can be direct code, a platform integration (Shopify, WooCommerce), server-side Google Tag Manager or Meta's Conversions API Gateway. TikTok, Google Ads, LinkedIn and Snap offer similar server-side APIs.
Conversions API (CAPI) pros and cons
Pros
- Not affected by ad blockers or browser cookie limits
- Reports events after the page has closed, such as webhook-confirmed payments
- Better matching when hashed email addresses or phone numbers are included
- You control exactly which data leaves your server
Cons
- Needs backend work, an access token and careful hashing
- Without deduplication, conversions get counted twice
- Consent rules still apply, so server-side is not a loophole
When to use Conversions API (CAPI)
Pick it when
- Meta ads are a meaningful part of your marketing spend
- Purchases or leads are confirmed on the server, for example by a payment webhook
- Pixel data is visibly missing conversions
Skip it when
- You do not advertise on Meta's platforms
- A small test campaign where the Pixel alone is enough
Conversions API (CAPI) pricing
Free
Free to use. Costs come only from the server, gateway or partner tool that sends the events.
Approximate, checked September 2026.What the other tools cost
Conversions API (CAPI) vs the alternatives
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