---
title: "A recipient bounced"
method: POST
path: "message.bounced"
---

# A recipient bounced

`POST message.bounced` (webhook)

Sent to your endpoint for `message.bounced`. Respond with a 2xx within 10 seconds; timeouts and non-2xx responses are retried on a backoff (7 attempts in total over about 21 hours). Redirects are not followed.

## Headers

- `X-SuperMail-Event` 'message.bounced', required
- `X-SuperMail-Delivery` string, required
- `X-SuperMail-Timestamp` string, required
- `X-SuperMail-Signature` string, required

## Payload

- object: Every webhook POST body. Verify `X-SuperMail-Signature: t=<unix>,v1=<hex>` where hex = HMAC-SHA256(secret, `<t>.<raw body>`), and reject timestamps more than 5 minutes old.
  - `id` string, required: Delivery id (also `X-SuperMail-Delivery`).
  - `event` 'message.bounced', required
  - `createdAt` string, date-time, required
  - `data` object, required: `message.bounced` — a recipient bounced; hard bounces are suppressed automatically.
    - `mailbox` string, email
    - `recipient` string, email
    - `hard` boolean
    - `detail` string

## Acknowledgement `200`

Acknowledged.

---

[API](https://skmtc.dev/supermailos/apis/supermailos-api.md) · [All operations](https://skmtc.dev/supermailos/apis/supermailos-api/llms.txt) · [OpenAPI document](https://skmtc.dev/supermailos/apis/supermailos-api/revisions/5bd0ce2ee269?raw)