What is an interstitial ad?

Why it earns more

An interstitial takes the whole screen and the whole attention. There is nothing else to look at and the user must act to proceed, so viewability is total and engagement rates are far above banner inventory.

That translates directly into price: interstitial eCPM typically runs many times higher than banner eCPM on the same audience, which is why publishers keep them despite the friction.

Timing is the whole craft

The format is defined by interruption, so the only variable that matters is what it interrupts.

Shown at a genuine transition — between levels, after a task completes, when the user is already pausing — an interstitial is tolerated. Shown mid-task, during content, or immediately on launch, it is experienced as an obstruction and drives uninstalls.

The commercial mistake is treating frequency as the lever. Halving the frequency of badly-timed interstitials produces half as much irritation and the same underlying problem; moving them to real transition points is what changes the outcome.

• Never on app launch. The highest-friction moment available.
• Never mid-task, including mid-scroll and mid-form.
• Cap per session, not only per day.
• Make the dismiss control real. Deliberately small close buttons drive accidental clicks, which platform policy increasingly treats as a violation.

The conversational parallel

There is no interstitial equivalent inside an AI conversation, and it is worth understanding why, because the reasoning generalises.

An interstitial works when the user is between tasks. A conversation has no between — it is one continuous exchange, and any full-screen interruption lands mid-task by definition. Attempts to insert one before a response is generated are experienced as the assistant withholding the answer for payment, which is the single most damaging thing an assistant can do to itself.

This is why AI formats attach to the response rather than blocking it: the surface has no natural pause to occupy.