Back to Catalog
Integration
Messaging Endpoints
Durable Subscriber
Go offline, come back — your messages will be waiting. No missed events.
Intent & Description
Real-world Use Case
Inventory sync service with scheduled maintenance windows — durable subscription to ProductUpdated events. During 2-hour maintenance, 500 product updates are published. On restart, inventory service receives all 500 queued events and syncs to current state before going live. Zero missed updates.
Source
📌 TL;DR
Durable Subscriber = your subscription survives downtime. Missed messages queue up, delivered on reconnect. Essential for any critical subscriber that cannot afford to miss events.
Advantages
- No message loss during planned or unplanned downtime
- Transparent catch-up on reconnect — subscriber processes missed messages automatically
- Enables scheduled maintenance without data loss
- Reliable delivery guarantee for critical event subscribers
Disadvantages
- Broker must store messages during absence — storage cost grows with offline duration
- Slow or never-reconnecting subscribers create unbounded message backlogs
- Catch-up processing can be slow and delay real-time event processing after restart
- Subscription lifecycle management (cleanup of abandoned durable subs) is needed