Quick answer
Firebase documents transaction duration as 270 seconds; 60-second idle expiration. Idle time can end a transaction well before the total-duration ceiling.
Verified Aug 22, 2026Official source
Current limits
| Constraint | Current value | Scope | Verified source |
|---|---|---|---|
| transaction durationIdle time can end a transaction well before the total-duration ceiling. | 270 seconds; 60-second idle expiration | Cloud Firestore | FirebaseAug 22, 2026 |
Why does this limit matter?
External network calls inside a transaction increase contention and can trigger the idle limit.
This value is scoped to Cloud Firestore; a different plan, runtime, model, endpoint, region, or account can produce a different effective constraint.
What should you check?
- Time read, compute, and write phases and remove unrelated I/O from the transaction.
- Confirm the exact plan, model, runtime, endpoint, region, and account that serve the failing workload.
- Record the observed value, response headers or configuration, timestamp, and source without logging secrets.
Important caveats
- Retries can repeat the transaction function, so side effects must stay outside it.
- Treat the official source and live account configuration as authoritative if they differ from this verified snapshot.
HyperObserve reports the documented platform constraint. Your application, SDK, gateway, provider, region, or account can impose a lower effective limit.
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