Service Bus quotas

This section lists basic quotas and throttling thresholds in Azure Service Bus messaging.

Messaging quotas

The following table lists quota information specific to Azure Service Bus messaging. For information about pricing and other quotas for Service Bus, see Service Bus pricing.

Quota name Scope Notes Value
Maximum number of Basic or Standard namespaces per Azure subscription Namespace Subsequent requests for additional Basic or Standard namespaces are rejected by the Azure portal. 100
Maximum number of Premium namespaces per Azure subscription Namespace Subsequent requests for additional Premium namespaces are rejected by the portal. 25
Queue or topic size Entity Defined upon creation of the queue or topic.

Subsequent incoming messages are rejected, and an exception is received by the calling code.
1, 2, 3, 4 GB or 5 GB.

In the Premium SKU, and the Standard SKU with partitioning enabled, the maximum queue or topic size is 80 GB.
Number of concurrent connections on a namespace Namespace Subsequent requests for additional connections are rejected, and an exception is received by the calling code. REST operations don't count toward concurrent TCP connections. NetMessaging: 1,000.

AMQP: 5,000.
Number of concurrent receive requests on a queue, topic, or subscription entity Entity Subsequent receive requests are rejected, and an exception is received by the calling code. This quota applies to the combined number of concurrent receive operations across all subscriptions on a topic. 5,000
Number of topics or queues per namespace Namespace Subsequent requests for creation of a new topic or queue on the namespace are rejected. As a result, if configured through the Azure portal, an error message is generated. If called from the management API, an exception is received by the calling code. 1,000 for the Basic or Standard tier. The total number of topics and queues in a namespace must be less than or equal to 1,000.

For the Premium tier, 1,000 per messaging unit (MU). Maximum limit is 4,000.
Number of partitioned topics or queues per namespace Namespace Subsequent requests for creation of a new partitioned topic or queue on the namespace are rejected. As a result, if configured through the Azure portal, an error message is generated. If called from the management API, the exception QuotaExceededException is received by the calling code. Basic and Standard tiers: 100.

Partitioned entities aren't supported in the Premium tier.

Each partitioned queue or topic counts toward the quota of 1,000 entities per namespace.
Maximum size of any messaging entity path: queue or topic Entity - 260 characters.
Maximum size of any messaging entity name: namespace, subscription, or subscription rule Entity - 50 characters.
Maximum size of a message ID Entity - 128
Maximum size of a message session ID Entity - 128
Message size for a queue, topic, or subscription entity Entity Incoming messages that exceed these quotas are rejected, and an exception is received by the calling code. Maximum message size: 256 KB for Standard tier, 1 MB for Premium tier.

Due to system overhead, this limit is less than these values.

Maximum header size: 64 KB.

Maximum number of header properties in property bag: byte/int.MaxValue.

Maximum size of property in property bag: No explicit limit. Limited by maximum header size.
Message property size for a queue, topic, or subscription entity Entity The exception SerializationException is generated. Maximum message property size for each property is 32,000. Cumulative size of all properties can't exceed 64,000. This limit applies to the entire header of the BrokeredMessage, which has both user properties and system properties, such as SequenceNumber, Label, and MessageId.
Number of subscriptions per topic Entity Subsequent requests for creating additional subscriptions for the topic are rejected. As a result, if configured through the portal, an error message is shown. If called from the management API, an exception is received by the calling code. Standard tier: Each subscription counts against the quota of 1,000 entities, that is, queues, topics, and subscriptions, per namespace.

Premium tier: 2,000.
Number of SQL filters per topic Entity Subsequent requests for creation of additional filters on the topic are rejected, and an exception is received by the calling code. 2,000
Number of correlation filters per topic Entity Subsequent requests for creation of additional filters on the topic are rejected, and an exception is received by the calling code. 100,000
Size of SQL filters or actions Namespace Subsequent requests for creation of additional filters are rejected, and an exception is received by the calling code. Maximum length of filter condition string: 1,024 (1 K).

Maximum length of rule action string: 1,024 (1 K).

Maximum number of expressions per rule action: 32.
Number of SharedAccessAuthorizationRule rules per namespace, queue, or topic Entity, namespace Subsequent requests for creation of additional rules are rejected, and an exception is received by the calling code. Maximum number of rules: 12.

Rules that are configured on a Service Bus namespace apply to all queues and topics in that namespace.
Number of messages per transaction Transaction Additional incoming messages are rejected, and an exception stating "Cannot send more than 100 messages in a single transaction" is received by the calling code. 100

For both Send() and SendAsync() operations.