Keep incoming Slack requests clean and safe with controlled, single run processing. The flow prevents duplicate work, avoids race conditions, and routes each request to the right path. It is ideal for teams that get many webhook events and need stable handling.

The webhook node receives the request, then a code step parses the payload and sets a unique value for locking. Redis checks if a lock already exists. If no lock is found, the flow sets a short lived lock with a 180 second expiry. If a lock is present, a wait step polls and a check decides if the event is a duplicate and should be skipped. A switch node routes the request to one of three paths. Each path finishes by removing the Redis key to release the lock and end cleanly.

You will need a Redis database and a Slack app that can send requests to the n8n webhook URL. Set the same lock key across check, set, and delete so the cleanup works. Expect fewer double runs, safer routing, and less manual cleanup. This is useful for actions from Slack buttons, command results, or any repeated webhook events.

• Incoming webhook captures Slack requests and passes the full body to the flow
• Code node parses the payload and sets a unique lock value from the request
• Redis get checks for an existing lock key before any work starts
• Conditional checks decide whether to acquire a lock or wait and recheck
• Redis set acquires the lock with a 180 second time to live
• Wait with polling helps avoid race conditions and filters duplicates
• Switch node routes events to one of three downstream paths
• Redis delete clears the lock key so the next request can run

• Eliminate duplicate runs for retried webhooks
• Reduce manual reprocessing from hours to minutes
• Handle high traffic by serializing conflicting events
• Improve data accuracy by avoiding double entries
• Connect Slack and Redis without custom scripts

1. Import the template into n8n: Create a new workflow in n8n > Click the three dots menu > Select 'Import from File' > Choose the downloaded JSON file.
2. You'll need accounts with Slack and Redis. See the Tools Required section above for links to create accounts with these services.
3. Prepare Redis: create a Redis database or use a managed Redis. Note the host, port, password, and TLS setting if required.
4. In n8n, open Credentials > New > search for Redis > create a Redis credential. Enter host, port, and password. Click Test and save with a clear name like Redis Prod.
5. Open the Incoming Webhook Data node. Copy the Test URL. In your Slack app settings, enable Interactivity or events that send requests, and paste the n8n webhook URL. Save changes.
6. In the Code node, confirm the payload path. If using Slack interactive payloads, keep the JSON parse of body.payload. If your source differs, adjust the JSON path and the variable used for the lock value.
7. Ensure the Redis keys match. Use the same key name in Check Redis Lock, Acquire Redis Lock, and Discard Redis Lock. Keep the TTL at 180 seconds or adjust to your needs.
8. Open the Workflow Switch node and define rules that route to Workflow 1, Workflow 2, or Workflow 3 based on fields in the parsed payload.
9. Connect each route to your real processing steps. Keep the Discard Redis Lock node at the end of each path so the key is always removed.
10. Run a live test. Trigger a Slack action twice in quick succession. The first run should process and the second should be skipped or delayed until the lock clears.
11. If Slack shows errors, verify the webhook URL is reachable from the internet. If Redis fails to connect, check credentials, firewall rules, and TLS settings. If locks remain, confirm the delete node uses the same key and is always reached.