Slack Trigger Setup

Questions
1

I’m trying to get the Slack Trigger set up. I have the app set up and the credentials working, but when I enable Event Subscriptions and paste the webhook URL into Slack, I get the following error message.

“Your URL didn’t respond with the value of the challenge parameter”

2

It looks like your topic is missing some important information. Could you provide the following if applicable.

  • n8n version:
  • Database (default: SQLite):
  • n8n EXECUTIONS_PROCESS setting (default: own, main):
  • Running n8n via (Docker, npm, n8n cloud, desktop app):
  • Operating system:
3

@smittym , you seem to be in the process of setting app your Slack application. Here’s the step you are missing, Events API | Slack.

Before your setup is completed you need to confirm your n8n workflow is the webhook you authorize to handle Slack events. This is a one-off task you have to complete before continuing with building your workflow.

To be more specific, when setting up a Slack app, you are asked to confirm your webhook URL. At this point, Slack sends HTTP request in the form

{
    "token": <token>,
    "challenge": <challenge>,
    "type": "url_verification"
}

What your n8n workflow has to do is to check that if type has the value “url_verification”, you respond back with the value of challenge. Once done Slack will aprove your webhook URL and you can move on.

4

I thought the Slack Trigger node would handle that verification. I can’t see any way to pass that challenge back to Slack from the Slack Trigger node setup.

5

Apologies, I missed that you are trying the trigger node. Indeed, verification should be done automatically.

Perhaps you are using wrong URL (test vs production) or n8n app does not reply in time or event does not even reach n8n (could be with self-hosted solution).

6

So, I am using cloud and I have verified the URL is correct. Maybe it times out, not sure how I would be able to track that down.

7

@smittym, I tested the setup on the cloud and had no issue. Perhaps it is a matter of following the steps to set this all up.

Here’s what I did

  1. Activate n8n workflow (where you have the Slack trigger), this essentially switches to Production mode
  2. Copy the production URL of the webhook
  3. Paste this URL into the Slack app configuration in “Event Subscriptions”

These steps have automatically verified the webhook URL for me.

image
image1350×546 47.2 KB

8

For some reason, without any changes, it started working today. I suspect there may have been some issue on the n8n side that was just a temporary glitch. Thank you for your help.