AWS Security ChangesHomeSearch

AWS eventbridge: Restructure EventBridge quotas: Custom Event Bus, Classic, API destinations

Service: eventbridge · 2026-09-27 · Documentation low

File: eventbridge/latest/userguide/eb-quota.md

Summary

Reorganizes the EventBridge quotas page: renames 'EventBridge event bus quotas' to 'Custom Event Bus quotas', adds new Service Quotas and fixed-limits tables for the Custom Event Bus (including a resource policy size quota and the PolicyLengthExceededException behavior), adds a 'Custom Event Bus - Classic quotas' section, and a new 'API destinations and connections' section covering account-wide quotas for both bus types. Also updates nav labels and the page footer link from 'Troubleshooting' to 'Tags'.

Security assessment

The change is primarily a quotas-documentation restructure (new Service Quotas and fixed-limit tables, renamed sections, nav/footer label updates). The only security-adjacent content is the resource-policy size quota (20,480 bytes) and the note that oversized policies fail with PolicyLengthExceededException, plus mention of AWS RAM-written policies not counting toward the quota; this touches access-control policy management but documents nothing new about a vulnerability, mitigation, or security best practice, and no CVE/advisory is referenced.

Evidence

+If the `default` policy in a `PutResourcePolicy` call exceeds the resource policy size quota, the call fails with `PolicyLengthExceededException`. See [Write a custom resource policy](./eb-custom-bus-sharing.html#eb-custom-bus-access-policy).

Diff

diff --git a/eventbridge/latest/userguide/eb-quota.md b/eventbridge/latest/userguide/eb-quota.md
index 8c9d4c3ee..c943e8e47 100644
--- a//eventbridge/latest/userguide/eb-quota.md
+++ b//eventbridge/latest/userguide/eb-quota.md
@@ -7 +7 @@
-EventBridge event bus quotasSchema Registry quotasPipes quotas
+Custom Event Bus quotasCustom Event Bus - Classic quotasAPI destinations and connectionsSchema Registry quotasPipes quotas
@@ -11 +11,5 @@ EventBridge event bus quotasSchema Registry quotasPipes quotas
-The following quotas apply to the various feature areas of Amazon EventBridge.
+The following quotas apply to the Custom Event Bus, to Custom Event Bus - Classic, to the API destinations and connections that both buses deliver to, to the schema registry, and to EventBridge Pipes.
+
+###### Note
+
+If you use Custom Event Bus - Classic, the event bus that routes with rules and targets, see Custom Event Bus - Classic quotas.
@@ -15 +19,5 @@ The following quotas apply to the various feature areas of Amazon EventBridge.
-  * EventBridge event bus quotas
+  * Custom Event Bus quotas
+
+  * Custom Event Bus - Classic quotas
+
+  * API destinations and connections
@@ -28 +36 @@ For a list of the quotas for EventBridge Scheduler, see [Quotas for EventBridge
-## EventBridge event bus quotas
+## Custom Event Bus quotas
@@ -30 +38,44 @@ For a list of the quotas for EventBridge Scheduler, see [Quotas for EventBridge
-EventBridge event buses have the following quotas.
+The Service Quotas console lists 6 quotas for the Custom Event Bus under Amazon EventBridge, each with an `[EventsV2]` prefix; 4 of them are adjustable. To raise the bus limit, for example, request an increase to `[EventsV2] Event Buses`. The other limits in this section are fixed values that the API enforces and are not adjustable. These quotas are separate from the Custom Event Bus - Classic quotas in Custom Event Bus - Classic quotas.
+
+### Service Quotas
+
+The following table lists the quotas in the Service Quotas console, per account per Region.
+
+Quota| Default| Adjustable  
+---|---|---  
+Event buses owned by the account. Buses shared with the account do not count| 5| Yes  
+Event sources owned by the account| 200| Yes  
+Subscribers per bus the account owns, counting every account the bus is shared with| 10,000| Yes  
+Size, in bytes, of the `default` resource policy of a bus the account owns. The `AWS_RAM` policy that AWS RAM writes for a shared bus does not count| 20,480| Yes  
+Events per second per bus, counting every event source and every account the bus is shared with| 500,000| No  
+Ingestion per event group per second, counted as the number of events plus their total size in KB in any one-second window| 1,500| No  
+  
+Your account's bus count is also published as the `ResourceCount` metric in the `AWS/Usage` namespace, so you can alarm before you reach the limit; see [Observability for the Custom Event Bus: metrics, logs, and CloudTrail](./eb-custom-bus-observability.html). Publishing and subscriber management are throttled separately for each account: `PutEvents` and `PutRawEvents` draw from one budget, and `CreateSubscriber` and `DeleteSubscriber` from another. Handle `ThrottlingException` with backoff and retry.
+
+If the `default` policy in a `PutResourcePolicy` call exceeds the resource policy size quota, the call fails with `PolicyLengthExceededException`. See [Write a custom resource policy](./eb-custom-bus-sharing.html#eb-custom-bus-access-policy).
+
+### Fixed limits
+
+The following values are set by the API and cannot be raised. Where a setting takes a range, you choose any value in the range; the maximum is the fixed part.
+
+Setting| You choose| Fixed maximum or value  
+---|---|---  
+`StorageConfiguration.RetentionPeriodInDays`| 1 to 365 days| 365 days  
+`RetryPolicy.MaxRetryAttempts`| 0 to 185, default 5| 185  
+`RetryPolicy.MaxEventAgeInSeconds`| 60 to 86,400, default 300| 86,400 seconds  
+`BatchConfiguration.MaxBatchSize`| 1 to 500| 500  
+`BatchConfiguration.MaxBatchWindowInSeconds`| 0 to 300, default 0| 300 seconds  
+`InvocationTimeoutSeconds` on Lambda, Step Functions, and HTTP targets| 1 to 30, default 30| 30 seconds  
+Entries per `PutEvents` or `PutRawEvents` request| 1 to 100| 100  
+Deduplication window| Not configurable| 300 seconds  
+JSONata expression in a `Transformer` or a target parameter| Not configurable| 8,192 characters  
+JSONata expression in a universal target's `Input`| Not configurable| 262,144 characters  
+Filters in one `FilterConfiguration`| Up to 3, one per scope| 4,096 bytes across all filters; 1,000 `$or` combinations  
+Filter changes per subscriber| Not configurable| 24 in any rolling 24 hours; see [Updating, pausing, and resuming a subscriber](./eb-custom-bus-update.html)  
+Subscriber creates or deletes in progress on one bus| Not configurable| 1 across all accounts; a second call fails with `ConcurrentModificationException`  
+Subscribers replaying from a past position at the same time| Not configurable| Limited per bus; `CreateSubscriber` fails with `LimitExceededException` when reached  
+`errorMessage` in a dead-letter record| Not configurable| 1,024 characters  
+  
+## Custom Event Bus - Classic quotas
+
+Custom Event Bus - Classic has the following quotas. The Service Quotas table also lists the API destination, connection, and global endpoint quotas, which are account-level resources.
@@ -59,0 +111,4 @@ Connections (Private) | Each supported Region: 20 |  The maximum number of priva
+## API destinations and connections
+
+API destinations and connections belong to your account, not to a bus, and both buses use them: a Custom Event Bus - Classic rule targets an API destination, and a Custom Event Bus subscriber delivers to one through `HttpParameters`. A Custom Event Bus producer that publishes Avro or Protobuf with a Confluent schema registry also names a connection. One set of quotas covers all of that use. In the Service Quotas table in Custom Event Bus - Classic quotas, the rows _Api destinations_ , _Connections_ , and _Rate of invocations per API destination_ are the account-wide values; the invocation rate is shared by every rule and subscriber that targets the same API destination. The fixed table in the same section lists the private connection limit.
+
@@ -126 +181 @@ To use the Amazon Web Services Documentation, Javascript must be enabled. Please
-Troubleshooting
+Tags