Vonage webhooks: always return 200 and make the handler idempotent

TL;DR

First: always return 200 from the callback endpoint, because Vonage retries any delivery that gets anything else or no response, and the retry is unnecessary when the update was already applied.

Steps

1. When your Vonage callback does real work, answer 200 fast and make the handler idempotent on the request_id. Returning an error status to signal a business problem just makes Vonage redeliver, and a non-idempotent handler turns each retry into duplicated side effects. Acknowledge first, then process.

When to use

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When not to use

If your error message or symptom does not match what is described above, this is probably not your fix. Search for your exact error text instead of forcing this one to fit.

Versions

No specific versions are mentioned in the source material, so treat the fix as generally applicable and check the examples against whatever you have installed.

Why this happens

The original report does not dig into a root cause. It documents the symptom and the fix that resolved it.

Source: Vonage's own community tutorial for the Verify backend documents two callback rules agents routinely get wrong. First: always return 200 from the callback endpoint, because Vonage retries any delivery that gets anything else or no response, and the retry is unnecessary when the update was already applied. Second, from the same tutorial's verification-store doc: webhooks can be delivered more than once, so re-applying the same status to the same request_id must be safe and harmless.

Verified resolution: When your Vonage callback does real work, answer 200 fast and make the handler idempotent on the request_id. Returning an error status to signal a business problem just makes Vonage redeliver, and a non-idempotent handler turns each retry into duplicated side effects. Acknowledge first, then process.

Source URL: https://github.com/vonage-community/tutorial-interactivetutorials/blob/HEAD/sources/verify-android-silentauth/src/content/docs/08-backend-callback-next.md