Disabling concurrent workflow executions?

Questions
1

In one of my workflows, concurrent workflow executions are causing duplication issues in my DB. Webhook triggers from the inbound API are happening at the exact same time and triggering concurrent executions of the same workflow in n8n. I am unable to control the root cause of the duplicates coming from the triggering webhook, and so I built a duplicate check in the worfkow to ignore the incoming data if it has already been added to the DB. Unfortunately, concurrent executions of my workflow fails to check if it’s a duplicate (since it’s processing at the exact same time).

Screen Capture 2025-11-24 at 10.35.06
Screen Capture 2025-11-24 at 10.35.06306×230 10.9 KB

As such, a queue for my workflow would likely fix this issue. n8n cloud allows for up to 20 concurrent executions at the same time for my entire instance and I don’t mind this for my other workflows, but it really causes an issue on this specific flow. If the only solution is to turn off concurrent executions for the entire instance, so be it; although it would be great to manage it per workflow. Is that possible? Or should this be a feature request?

Screen Capture 2025-11-24 at 10.55.02
Screen Capture 2025-11-24 at 10.55.021757×401 75.6 KB

  • n8n version: 1.120.4
  • Running n8n via: n8n cloud
2

Hey @xhi-nico Welcome!

Interesting problem! I guess because you’re having to update/fetch from Notion in a loop, it’s not going to be fast enough to flag duplicates to other executions. Have you tried using Datatables instead?

You could build something very similar to Prevent simultaneous workflow executions with Redis | n8n workflow template but without the additional dependency.

Also check out upstash.com for queues on the cheap.

3

Thanks for the thoughts Jim. Was hoping to avoid using Redis / other tools to build a queue, this would be a great n8n feature to have built in for specific workflows.

Either way, I managed to bandaid this problem with a simple random wait node:
Screen Capture 2025-12-24 at 10.16.34

This way when the triggers occur at the exact same time, at least the random wait takes care of it.

Thanks again :slight_smile:

4

The inability to have concurrency limit on individual workflows is… wild

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