An offer cap is a ceiling set by the advertiser. Once it is reached, further activity stops being accepted until the window resets. Caps are ordinary campaign hygiene on the buy side and a serious user-experience concern on the sell side, because a user who completes a capped-out offer has done the work for nothing.

How it works

The advertiser sets a limit and a period. The platform tracks usage against it and reports how much allowance remains. A wall reads that allowance before displaying an offer and hides the offer once it is exhausted.

The two kinds of cap

• Conversion caps limit how many completions the advertiser will pay for. This is the common case and the one that directly bounds spend.

• Click caps limit traffic rather than outcomes, used when an advertiser wants to control landing-page load or test at a fixed volume.

Both operate over a defined window. Hourly and daily caps are typical for pacing a budget evenly, weekly and monthly for holding to a period target, and a total cap sets a lifetime ceiling after which the offer closes for good.

Why publishers should respect caps

Traffic sent to an exhausted offer converts and then does not credit, which is precisely the failure that erodes trust in a wall. The user sees a completed action and no reward, and has no way to tell that from the wall being broken. Checking remaining allowance before serving is the difference between a clean experience and a support queue.

Caps and dayparting

Caps limit how much of an offer runs; dayparting limits when it runs. They are frequently used together, and both need checking before an offer is shown. An offer that is inside its cap but outside its scheduled hours is just as unable to pay as one that has run out.

Caps and wall ranking

Caps interact badly with static offer ordering. A high-EPC offer pinned to the top of a wall will exhaust its cap early in the day, after which the best position on the wall is occupied by something that cannot pay. Walls that re-rank against live availability avoid this; walls that sort once and cache do not. The symptom is a revenue curve that falls off sharply partway through each day for no apparent reason.

Common mistakes to avoid

• Caching offer availability too long. Caps move continuously, and a stale list serves offers that closed hours ago.

• Showing a capped offer greyed out rather than hiding it. A visible offer nobody can complete generates support contacts, not engagement.

• Ignoring the reset window. An offer capped hourly returns shortly; one at a total cap never does.

• Treating cap exhaustion as a tracking fault. It is the system working, and the right response is to stop serving the offer.