# Create a webhook subscription with the PostEverywhere API

**Source:** https://posteverywhere.ai/docs/api/create-webhook

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[🤖Connect ChatGPT, Claude or any AI agent to manage your social media end to endConnect your AI agent to manage your social media](https://posteverywhere.ai/agents)POST/webhooks

# Create a webhook subscription with the PostEverywhere API

PostEverywhere POSTs event payloads to your URL, signed with
HMAC-SHA256 in the `X-PostEverywhere-Signature` header
(`sha256=<hmac>` over the raw body using the returned `secret`).
Delivery headers also include `X-PostEverywhere-Event`,
`X-PostEverywhere-Event-Id`, `X-PostEverywhere-Timestamp` and
`X-PostEverywhere-Delivery-Id`. The `secret` is returned ONLY on
creation. URLs are SSRF-validated (no localhost/private/metadata
addresses). Max 25 webhooks per organization
(`400 limit_reached`). Unknown events → `400 invalid_event_type`.

Guide: [Webhooks guide](https://posteverywhere.ai/docs/webhooks)

Copy MarkdownCopy for LLMThis endpoint accepts a JSON request body. See the [webhooks guide](https://posteverywhere.ai/docs/webhooks) for a worked example.

## Responses

- 201Created — includes the one-time signing secret
- 400
- 401
- 402
- 403
- 429
- 500

## More in Webhooks

- [List webhooks](https://posteverywhere.ai/docs/api/list-webhooks)
- [Get a webhook](https://posteverywhere.ai/docs/api/get-webhook)
- [Update a webhook](https://posteverywhere.ai/docs/api/update-webhook)
- [Delete a webhook](https://posteverywhere.ai/docs/api/delete-webhook)
- [Test a webhook](https://posteverywhere.ai/docs/api/test-webhook)
[← List webhooks](https://posteverywhere.ai/docs/api/list-webhooks)[Get a webhook →](https://posteverywhere.ai/docs/api/get-webhook)[← All endpoints](https://posteverywhere.ai/docs/api/reference)