A postback is how a conversion travels from the advertiser back to your tracker, without relying on browser cookies.
Main points
- A postback is a server-to-server message that reports a conversion back to the network or your tracker.
- It works by passing a unique click ID through the tracking link and returning it with the conversion.
- Server-to-server tracking doesn’t depend on browser cookies, so it’s more reliable than pixel tracking.
- Always test a postback before sending real traffic.
In CPA marketing, you need to know which clicks became conversions. Postback tracking does this by passing an ID through the funnel and back again.
How it works
- A visitor clicks your tracking link. Your tracker or network creates a unique click ID.
- The click ID is passed to the advertiser in the offer URL.
- The visitor converts on the advertiser’s site.
- The advertiser’s system calls your postback URL, including the click ID and sometimes the payout.
- Your tracker matches the click ID and records the conversion against the original click.
Postback vs. pixel tracking
| Postback (server-to-server) | Pixel (browser-based) | |
|---|---|---|
| Fires from | Advertiser’s server | Visitor’s browser |
| Affected by cookies and blockers | No | Yes |
| Setup | Needs the click ID passed correctly | Needs code on the thank-you page |
| Reliability | Generally higher | Can miss conversions |
Testing a postback
- Generate a test click through your tracking link.
- Ask the network or advertiser for a test conversion, or fire the postback URL with that click ID.
- Check that the conversion appears in your tracker with the right ID and value.
Pro tip
Write down the exact parameter names each network uses for click IDs and payouts. Most postback problems come from a renamed or missing parameter.
Good practice
Postbacks carry identifiers, not personal details. Avoid passing names, emails or phone numbers in tracking URLs, both for privacy and because URLs are often logged.
Building reliable tracking
Combine postbacks with sub IDs so you know which traffic source each conversion came from, and understand the network’s attribution window so late conversions don’t surprise you.
Frequently asked
What’s the difference between a postback and a pixel?
A pixel fires from the visitor’s browser on the thank-you page. A postback is sent directly between servers, so browser settings and blockers don’t affect it.
What is a click ID?
A unique identifier created for each click. It travels with the visitor and comes back with the conversion, so the conversion can be matched to the click.
Why is my postback not firing?
Common causes are a missing or renamed parameter, a typo in the postback URL or the advertiser not passing the click ID back.
This article is general information for marketers, not legal advice. Advertising, privacy and consumer protection rules vary by country and change over time, so check the current rules and your network’s terms, and get legal advice where needed before running campaigns.