Summary
Firebase marked an iOS Google Analytics for Firebase incident resolved after an incorrectly formatted payload caused launch crashes. The reported crash counts came from one production app.
Firebase maintainers marked an incident affecting Google Analytics for Firebase on iOS resolved after an incorrectly formatted payload caused apps to crash on launch. In a report on the Firebase iOS SDK repository, one app operator traced crashes to the SDK’s handling of an experiment response. Firebase said the incident began on 28 September 2026 at 17:41 US/PDT and was fully resolved at 23:52 US/PDT.
What triggered the crashes
The app operator reported that their production app began crashing without a new app release, across four already-released builds. The report recorded 56 crashes among 56 users during the first 18 minutes; the operator said all 42 crash traces they checked followed a response to Firebase’s sdk-exp endpoint.
The reported exception was NSInvalidArgumentException: -[__NSDictionaryM setObject:forKeyedSubscript:]: key cannot be nil. The stack trace places the crash while the Analytics SDK was processing an experiment response and copying experiment data into a snapshot. The issue reporter suspected the payload was being parsed into a nil key; Firebase’s pinned update described the cause as an incorrectly formatted payload received by the SDK.
In Objective-C, a mutable dictionary cannot use nil as a key. Attempting to set an entry with a nil key raises an exception, which explains why malformed data could terminate an app rather than simply produce an invalid experiment value. The report says the endpoint returned HTTP 200, showing that a successful HTTP response can still contain data the receiving software cannot process correctly.
Resolution and scope
Firebase said the incident was fully resolved and noted that crash-reporting delays could cause earlier crashes to appear in reports after the fix. The maintainer also said the team was investigating the root cause and steps to prevent a recurrence.
The figures in the issue report describe one app operator’s experience, not a total across Firebase customers. The report identifies Firebase iOS SDK version 12.14.0, but the incident update does not provide an overall count of affected apps or users.