Azure Service Bus Topic Filter Builder

About This Tool

The Azure Service Bus Topic Filter Builder helps you construct subscription filter rules for Azure Service Bus topics. Filters determine which messages from a topic are delivered to each subscription, enabling message routing patterns like content-based routing and pub/sub fanout. This tool supports SQL filters, correlation filters, and actions, generating the rule definitions you can apply via the Azure portal, CLI, SDK, or ARM templates.

When to Use This Tool

• •Build SQL filter rules that route messages based on custom properties like region, priority, or message type.
• •Create correlation filters for high-performance message routing based on system properties and user-defined properties.
• •Design filter rules with actions that modify message properties as they are delivered to subscriptions.
• •Build complex multi-subscription routing topologies where different consumers receive different subsets of messages.

Frequently Asked Questions

What is the difference between SQL filters and correlation filters?

SQL filters use a SQL-like expression syntax that can evaluate complex conditions on message properties. Correlation filters match on exact property values and are significantly faster because they use hash-based matching. Use correlation filters when you only need exact-match routing.

What happens to messages that do not match any subscription filter?

Messages that do not match any subscription filter are not delivered to that subscription. If no subscription filters match a message, it is essentially dropped from those subscriptions' perspectives. The message still remains in the topic until all active subscriptions have processed or filtered it.