Dedupe keys

Dedupe keys provide idempotent enqueue. When dedupe_key is supplied, append() returns False if a task with the same key is already in flight.

queue.append({"job": "once"}, dedupe_key="job-123")

Important details

• The dedupe index only applies to string values.
• Only tasks in new, pending, or failed are considered for uniqueness.
• When a task reaches successful, the dedupe key is no longer reserved.

When to use it

Use dedupe keys when you must prevent duplicate jobs (for example, one report per user per day).