General

• Order of webhooks is not guaranteed.
• The webhooks API provides "at least once" delivery of webhook events. This means that an endpoint might receive the same webhook event more than once.
• Webhook delivery isn't always guaranteed.

Failed delivery and retries

If your system does not respond with a status code between 200-299 within 30 seconds the webhook delivery is considered failed. Our system will wait for at least one minute to automatically retry sending the webhook message. This process is repeated up to five times. If sending the webhook message does not succeed the message is marked as failed in the webhook UI. The webhook UI offers two actions for failed messages:

• "Purge failed messages": deletion of all failed messages
• "Redeliver failed messages": trigger resending all failed messages

The redelivery of failed messages is not done at the same moment for all messages. Especially, if there is a large number of failed messages it can take time to deliver all failed messages.

We define the following changes as backwards-compatible

• Adding new properties or HTTP headers to responses
• Changing the order of properties
• Changing the format or length of primary id fields and keys without exceeding 255 characters