How long is the IPN timeout length?
PayPal's Instant Payment Notification (IPN) system expects your webserver to send an HTTP 200 response when the IPN is sent to your IPN script.
If your server doesn't respond after a certain amount of time, the IPN system then re-posts the IPN to your script.
The amount of time between each re-post doubles each time: 10 seconds, 20 seconds, 40 seconds, 80 seconds, and so on, up to a maximum of 24 hours. The IPN system stops re-posting when:
- PayPal receives a basic HTTP "200 OK" response from your web server, or
- When approximately four days have passed since the initial post.
Note: This functionality applies to both Sandbox and Live accounts.
How do I troubleshoot IPN?
Why didn't I receive any IPN posts?