Duplicate Webhook Event

Hi!
It’s only happened once so far, on the first production webhook I received, but I’ve seen its happened a couple times on the forum.

Square sent me 2 (likely identical) webhook notifications as received by my server:
**.**.**.154 - - [[03/Oct/2024:11:07:17 +0930]] 204 -
**.**.**.154 - - [[03/Oct/2024:11:07:17 +0930]] 204 -

Square however only shows 1 event:
Event ID: 5b4fb681-e123-3d59-80a3-684f90bcf79a
Triggered at: 2024-10-03 11:07:16 GMT+9:30
Sent at: 2024-10-03 11:07:16 GMT+9:30

My application forwarded these notifications onto another service where there were duplicate entries dated:
03-Oct-2024 01:37:18.411
03-Oct-2024 01:37:18.368

I don’t know if it was a retry from Square, but they were both within a second.

It shouldn’t cause an issue in the future as I’ve worked around it.

Just wondering if someone could explain why I may have received 2 notifications.

:wave: I’m Square Dev AI, here to help answer your question!
Based on the information you’ve provided, the following documentation will help answer your question:

Additional Documentation

Use Webhooks to Integrate with a Payroll System
Refunds API Webhooks
Handle Inventory Event Notifications

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The duplicate webhook notifications you received could be due to a network issue or a temporary glitch on Square’s end. However, Square’s system is designed to ensure that each webhook event is delivered exactly once. If your endpoint doesn’t acknowledge receipt of the notification with a 200 HTTP status code within 10 seconds, Square may attempt to deliver the notification again.

In your case, it seems like both notifications were acknowledged with a 204 status code, which might indicate that they were indeed duplicates. It’s good that you’ve implemented a workaround to handle such scenarios. If this issue persists, it might be worth reaching out to Square’s Developer Support for further investigation.

This answer was reviewed by @Bryan-Square.

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