Glossary
What is a ttclid?
The ttclid is TikTok’s click identifier: a parameter TikTok appends to your landing-page URL when a user clicks a TikTok ad. Sending the ttclid with conversions reported through the TikTok Events API links those events back to the specific ad click, which improves attribution and match rates.
When a TikTok ad is clicked, the visitor usually lands in TikTok’s in-app browser with ?ttclid=… on the URL. The TikTok pixel can store the value, and TikTok also sets a _ttp cookie that identifies the browser. The Events API accepts both as matching signals alongside hashed emails and phone numbers.
TikTok traffic is especially exposed to signal loss: an in-app browser plus a largely mobile, iOS-heavy audience means cookies are short-lived and client-side events frequently go missing. A conversion that happens days after the click often has no surviving ttclid in the browser.
Capturing the ttclid first-party at landing and storing it server-side solves this: when the order arrives, the stored click ID is attached to the Events API payload, so TikTok can attribute the conversion even though the browser context is long gone.