support

POST `/v1/webhooks/inbound-email`

Ingest a customer's support reply from the mail edge.

Authentication

This endpoint is public. It takes no credential and no organisation — it is what our own marketing site and AI answer engines read.

This endpoint takes no organisation id. Your key already identifies the organisation it belongs to, and the response is scoped to it.

Try it

Replace anything in angle brackets with your own values, and the key placeholder with a key from your dashboard.

curl -X POST https://api.zinndigital.com/v1/webhooks/inbound-email \
  -H "Content-Type: application/json" \
  -d '{ "from": <string>, "message_id": <string> }'

Signed in? The API console in your dashboard fills in your real organisation id and your own key, and runs the request against the live API so you can see the actual response. Open this endpoint in the API console

Details

**Unauthenticated by design** — the caller is a Cloudflare Email Routing Worker with no Zinn® credential, so an HMAC over `"<timestamp>\n<body>"` in `X-Zinn-Signature` *is* the authentication. The timestamp is inside the signed material and its skew is bounded, so a captured request cannot be replayed later. This is the inbound half of support email. Before it existed the platform sent notifications from an address that accepted mail and discarded it: a customer replied, nothing happened, and neither they nor the waiting staff member was told. The ticket is resolved from a **signed token inside the `Message-ID`** we set on the outbound notification — nothing in the body, the `From` address or any other header selects a tenant, because all of those are chosen by whoever sent the mail. Redelivery is the normal case, not the exception: email is at-least-once and a lost response guarantees a retry, so a message already filed answers `200` with `duplicate: true` rather than appending a second copy. ⛔ Unlike the gateway webhooks, a message that **cannot be routed is answered `422`**, not `200`. A 2xx tells the Worker to accept the mail, and an accepted message that reaches no ticket is the exact defect this endpoint exists to remove; `422` makes the Worker reject it so the sender's own mail server bounces it back to the customer.

Parameters

Name	Type	Required	What it is
`X-Zinn-Timestamp (header)`	`string`	Yes	Unix seconds. Inside the signed material; skew-bounded to five minutes.
`X-Zinn-Signature (header)`	`string`	Yes	`sha256=<hex>` HMAC over `"<timestamp>\n<body>"`.

Request body

Name	Type	Required	What it is
`from`	`string`	Yes	The envelope sender. Forgeable, and treated as such — it is checked against the ticket's org and the answer becomes a flag, never a permission.
`to`	`string`	No	—
`message_id`	`string`	Yes	The message's own `Message-ID`. Stored, and unique, so a redelivery cannot append twice.
`in_reply_to`	`string`	No	Carries the signed ticket token when the customer replied to one of our notifications.
`references`	`string`	No	The full thread chain. Searched as well as `in_reply_to`, because a reply to the third message in a thread puts our id here and not there.
`subject`	`string`	No	—
`text`	`string`	No	The message body. Quoted history is trimmed engine-side and the result is length-bounded.

Response

Name	Type	Required	What it is
`ticket_id`	`string`	Yes	—
`duplicate`	`boolean`	Yes	This exact message had already been filed — a success, not an error.
`sender_verified`	`boolean`	Yes	Whether the sender is a known address on the ticket's org. `false` still files the message, flagged for staff.
`reopened`	`boolean`	Yes	Whether filing it moved a `solved` ticket back to `open`.

Errors this endpoint can return

400 · 422 · 503

POST /v1/webhooks/inbound-email