Glossary

fbclid

The click identifier Meta appends to ad destination URLs. What it is for, what it is not, and why it cannot be your attribution backbone.

fbclid is the click identifier Meta appends to the destination URL of an ad click. It is part of the platform’s own tracking, and it exists so the platform can recognise a visit that originated from one of its ads.

What it is useful for

  • Sending conversions back to Meta through the Conversions API, where it improves matching.
  • A secondary key for reconciliation between your tracking and the platform’s reporting.

What it is not

  • Not a universal key. It exists only for Meta traffic. Other platforms have their own parameters (gclid for Google, ttclid for TikTok), and organic traffic has none.
  • Not self-describing. An fbclid does not tell you which ad it came from — that requires a lookup on the platform side.
  • Not under your control. It is generated by the platform and can be dropped by browser privacy features before it reaches your server.

The practical pattern

Store both, use one:

click_id  → your attribution key (first-party, yours)
fbclid    → sent back to Meta with the lead event

Last updated: 2026-09-21

FAQ

Can I use fbclid as my only attribution key?+

It is a poor sole key. It only exists for Meta traffic, it is only as reliable as the URL parameters that survive to your page, and it does not identify the ad without a lookup. Use your own click ID as the key and keep fbclid alongside it.

Keep reading

Tracking identifiersHow a click becomes a record you can act on: UTM parameters, click IDs and first-party cookies. What each one identifies, and where each one breaks.Meta CAPI — Conversions APIThe server-side interface for sending conversion events to Meta. Why deduplication matters, and how it differs from the browser pixel.

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