Retry mechanism

The retry mechanism resends webhook event requests that fail on the first attempt. Requests can fail for several reasons, including connection timeouts and client-side issues. Key points about retries:

• If the client’s servers are unresponsive, webhook event requests are paused for 10 minutes and then resumed.

• 4xx response codes, except for 429, and any 5xx response code stop all retry attempts and discard the webhook.

• There are 4 retry attempts, in addition to the original request.

  Each retry is sent with the following increments:

  • 1st attempt: 10 min
  • 2nd attempt: 1 hour
  • 3rd attempt: 2 hours
  • 4th attempt: 8 hours

  Reference example showing the retry mechanism runtime:

  Attempt Number	Delay	Time
  T1- Original attempt	0	10:00 am
  T1 + 10 min	10 min	10:10 am
  T2 + 1 hour	1 hour	11:10 am
  T3 + 2 hours	2 hours	1:10 pm
  T4 + 8 hours	8 hours	9:10 pm

This example includes the original attempt Brevo sends to the notify URL before failure, for 5 requests in total.