Send plain JSON to Mattermost using the AppRise notification

[smileBeda]

I am trying to send plain JSON to MatterMost because I need an interactive message in Mattermost and not just text.

So, I set the settings notification url to posts://my-domain/TOKEN and the payload a minimal JSON for now (it would of course be more extensive in real world).

The test notification fails with:

2025-11-07 17:46:54,925 - DEBUG - Loaded Custom HTTP - POSTS URL: posts://
2025-11-07 17:46:56,596 - WARNING - Exception in custom HTTP handler: 404 Client Error: Not Found for url: https://my-domain/TOKEN?format=text

Just to be sure I also tried the "unsafe" post and get the same error.

And, yes, it works with plain cURL:

curl -X POST \
  -H 'Content-Type: application/json' \
  -d '{
        "text": "Container *my-service* has an update available.",
        "attachments": [
          {
            "text": "Trigger update?",
            "actions": [
              {
                "name": "Update Docker",
                "integration": {
                  "url": "https://yourserver.local/update/my-service",
                  "context": {
                    "image": "my-service"
                  }
                }
              }
            ]
          }
        ]
      }' \
  https://my-domain/hooks/TOKEN

However, using the same URL in ChangeDetection says this is an invalid AppRise URL, so I have to use the posts://my-domain/TOKEN in there...

Also, I tried to verify if it is due to the appended ? parameter, but that makes no difference in cURL:

curl -i -X POST \ \
  -H 'Content-Type: application/json' \
  -d '{"text": "hello"}' \
  https://my-domain/hooks/TOKEN?format=text

... works just as fine

Based on that, I tried a changedetection / APpRise URL to posts like so:
posts://my-domain/hooks/TOKEN (which is the native url)

But then I get a 400 bad request instead of the 404.

So,

Note, otherwise these notifications work just fine of course, with my current mmost: setup. But they are not sending JSON, so interactive message is not possible. Just mentioning this to ensure its clear my host:token etc are NOT the issue here, they are available and fully working otherwise

[dgtlmoon]

Hey, yeah posts:// is the right one here, then you get full control

  posts://my-domain/hooks/TOKEN

should work.. but i dont have enough information (like your actual mattermost https url) to help.. try to paste here but change the secret keys to XXXX

without knowing more info, we cant help i think

However, using the same URL in ChangeDetection says this is an invalid AppRise URL, so I have to use the posts://my-domain/TOKEN in there...

what URL exactly? can you be more clear?

Yes, posts:// is the right one if it its POST you need

I believe this is because of the query parameter added - but I am not sure.

what query parameter? you didnt include any more info about this in your report, theres not enough info here

[smileBeda]

Sorry, my last reply crossed your reply, did not see it.

Yes it works, one just needs to add real JSON as well.

As for query parameter I mean the ?format=text appended to the notification url, but that's not the reason it doesn't work

Problem solved by using /hooks since this is a posts request it needs the real URL and adding proper JSON body.
Sorry the noise.

[dgtlmoon]

No problems, glad you solved it, sometimes just typing it up makes you think through it differently

[smileBeda]

Meh, I am an idiot.

The /hooks/ endpoint is correct but of course it needs proper JSON, which I missed in the body.
Problem solved.