Migration
Migrating a push audience off OneSignal without losing half of it
What actually transfers when you change push providers, what does not, and the two decisions that determine whether your migration is an import or a rebuild.
Notibase blog
How push notifications actually work, what breaks, and how to debug it — written by the people building the platform.
Web push
Rotating your VAPID keys unsubscribes every web push user
A browser push subscription is cryptographically bound to the key pair that created it. Change the keys and every existing subscriber goes silent — no error, no warning, no way back.
iOS
Why your iOS notification action buttons never appear
iOS does not read action buttons out of a push payload. It draws a category that your app registered — which is why the same payload that works on Android shows nothing on an iPhone.
FCM
Debugging FCM INVALID_ARGUMENT, in order of likelihood
The FCM HTTP v1 API returns INVALID_ARGUMENT for about a dozen unrelated mistakes and tells you almost nothing about which one you made. Here is the list, ordered by how often it is actually the cause.
Debugging
Expired, invalid, mismatched: three dead push tokens that need three different responses
Most platforms collapse every delivery failure into "failed". Three of the most common failures mean completely different things, and treating them the same is how you either lose real subscribers or keep sending into the void.