# Send a customer message



URL: https://getclickfix.com/docs/api-reference/api-channel/send-a-customer-message?lang=en

Sends a customer message to the API channel. The channel is set up under **Channels → Add channel → API**; the setup gives you the inbound URL (`{instance}`), the signing secret and a field for the URL agent replies are sent to.

The request is verified with the channel's signing secret, not an API key: `X-ClickFix-Timestamp` (Unix seconds) and `X-ClickFix-Signature: sha256=` + hex(HMAC-SHA256(secret, timestamp + "." + raw_body)). Requests whose timestamp is older than 5 minutes are rejected. A message with the same `id` is stored once. Retry on `5xx`.


This page is the API reference generated from the OpenAPI schema; request and response schemas, examples and curl/Node.js/Go/PHP requests are on the HTML page. Shared rules: https://getclickfix.com/docs/api.md?lang=en