I originally created a webhook in the developer playground and was successfully receiving data to my app, this stopped working when the playground credentials expired. I’ve since logged in to playground and deleted that webhook.
I have now registered a webhook direct from my app and successfully have a webhook id and the url for the webhook is the same as I used from the playground. However I’ve checked the access logs and there doesn’t seem to be any attempt from Monzo to even access that url after a transaction is created.
I’m seeing the same thing my end. My Heroku instance responds to ping commands so I know it’s working and I’ve even added a fake YNAB transaction via command line so I know the YNAB API is listening. After looking at my logs, my only conclusion is that Monzo is not triggering webhooks on transactions.
If I put the url as http instead of https, it appears Monzo makes an attempt to POST to the url when checking the access logs. However this won’t post the data because the POST data is not retained on http code 301.
If I put the url as https, no attempt is made by Monzo to contact the https url.