> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stateset.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Receives an **asynchronous MDN**: a partner POSTs the receipt for a message

> we sent earlier (AS2 async mode). We match it to the tracked delivery by Original-Message-ID, verify the disposition and — recomputing the MIC from the…

we sent earlier (AS2 async mode). We match it to the tracked delivery by
`Original-Message-ID`, verify the disposition and — recomputing the MIC from
the delivery's stored payload — the integrity check, then flip the delivery
to `delivered` (or `failed` with the partner's reason). Unauthenticated by
AS2 design; the match is to a Message-ID we minted, and a signed MDN must
verify against the partner's configured certificate before it can change
delivery state.

### Response

No response body. MDN processed (matched or ignored).

### Status codes

| Code  | Meaning                            |
| ----- | ---------------------------------- |
| `200` | MDN processed (matched or ignored) |
| `422` | Body is not a parseable MDN        |

<RequestExample>
  ```bash cURL theme={null}
  curl --request POST \
    --url 'https://edi.stateset.com/v1/as2/mdn' \
    --header 'Authorization: Bearer YOUR_API_KEY'
  ```
</RequestExample>