What causes rewarded ads being spoofed without server-side verification?

You grant rewards from the client earned-reward callback, which a modified client or proxy can trigger at will, so players claim rewards without watching ads.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Rewarded Ads Without Server-Side Verification Being Spoofed

Quick answer: Enable the ad network's server-side verification callback so the network notifies your backend of a genuine completion, and grant only on that server-to-server signal.

A cheater patches the client to fire the rewarded callback repeatedly and farms currency, because the client is trusted. Server-side verification (SSV) moves the trust to a network-to-server callback and fixes it.

How to fix it

1. Enable SSV in the network

Configure the rewarded ad unit's server-side verification URL (AdMob SSV, IronSource, etc.) so the network posts a signed completion to your backend.

2. Verify the SSV signature

On your endpoint, validate the network's signature/key and the transaction id before crediting, so a forged callback is rejected.

3. Grant only from the server

Have the client request its updated balance after the SSV grant rather than self-granting; the client callback becomes UI-only.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.