A postback is a server-to-server message that confirms a user completed an action. When something tracked happens, such as an install or a finished offer, one server tells another that it occurred, so data lines up and rewards are paid correctly. It is the quiet backbone of accurate conversion tracking in performance advertising.

How a postback works

When a user completes a tracked action, the advertiser's or network's server sends a message (the postback) to the publisher's server confirming it happened. Because the exchange is server-to-server, it is more reliable and harder to tamper with than client-side tracking.

The message carries the details that matter: which user, which offer, and often a payout value, tied together by a unique identifier. The receiving server matches that identifier to the right session and acts on it, all without the user's device having to be trusted as the record.

Why server-to-server beats client-side

Client-side tracking runs in the user's app or browser, where it can be blocked, lost, or faked. A postback travels directly between two servers, so it is far harder to intercept or spoof. For anything that pays out real money or currency, including rewarded and incentivized traffic, that reliability is the difference between a trustworthy reward system and one that leaks to fraud.

Why it matters

Postbacks make sure conversions are counted once, rewards are paid only for genuine completions, and both sides agree on what occurred, which is essential for trust and for fighting fraud. Without them, a publisher would be crediting rewards on the user's word alone. That single guarantee, that a reward only fires on a verified action, is what lets publishers open rewarded earning to their whole audience without inviting abuse.

Postbacks and offerwalls

On an offerwall, the postback is what triggers the user's reward and credits the publisher the moment an offer is completed. RevU uses reliable server-to-server postbacks so rewards land instantly and revenue is tracked accurately. The same signal that pays the user also updates the publisher's records, which keeps the reward economy honest and the earnings verifiable.

Postback vs. pixel

A tracking pixel fires from the user's device, on the client side, and is easy to lose or manipulate. A postback fires server to server and is authoritative. Many stacks still use pixels for lightweight web tracking, but rewarded and payout-critical flows lean on postbacks because the money involved demands a signal that cannot be faked from the device.

Common misconceptions

• A postback is not visible to the user. It happens between servers, not on screen.

• Postbacks are not instant by magic. Delays or misconfigured endpoints can hold up rewards, so they need monitoring.

• A postback confirms an action, not its quality. It says the offer completed, not that the user will stick around.