Mailbox API

Get a message

GET

/azure/v1.0/users/{email}/messages/{id}

const url = 'https://api.customers.ac/api/mailbox/v1alpha1/azure/v1.0/users/sender%40yourdomain.com/messages/example?%24select=id%2Csubject%2Cbody%2Cfrom%2CtoRecipients%2CreceivedDateTime';
const options = {method: 'GET', headers: {Authorization: 'Bearer <token>'}};

try {
  const response = await fetch(url, options);
  const data = await response.json();
  console.log(data);
} catch (error) {
  console.error(error);
}

curl --request GET \
  --url 'https://api.customers.ac/api/mailbox/v1alpha1/azure/v1.0/users/sender%40yourdomain.com/messages/example?%24select=id%2Csubject%2Cbody%2Cfrom%2CtoRecipients%2CreceivedDateTime' \
  --header 'Authorization: Bearer <token>'

Fetches a single message by id. Mirrors Graph’s GET /users/{id}/messages/{message-id}.

Use the id returned by List messages.

Authorizations

BearerAuth

Parameters

Path Parameters

email

required

string format: email

The mailbox address, which must belong to the account owning the API key. A mailbox that exists but is not yours returns 404 rather than 403, so this endpoint cannot be used to discover which addresses are sending.ac mailboxes.

Example

sender@yourdomain.com

required

string

Graph message id. Opaque and forwarded byte-for-byte — do not decode or re-encode it, as ids routinely contain =, + and /.

Query Parameters

$select

string

Example

id,subject,body,from,toRecipients,receivedDateTime

Responses

200

The message.

application/json

A Graph message. Only commonly used properties are listed; the full Graph resource is returned and accepted.

object

Opaque message id. Forward it byte-for-byte — ids contain =, + and /.

string

subject

string

body

object

contentType

string

default: text

Allowed values: text html

content

required

string

bodyPreview

string

from

object

emailAddress

required

object

name

string

address

required

string format: email

toRecipients

Array<object>

object

emailAddress

required

object

name

string

address

required

string format: email

ccRecipients

Array<object>

object

emailAddress

required

object

name

string

address

required

string format: email

receivedDateTime

string format: date-time

sentDateTime

string format: date-time

isRead

boolean

hasAttachments

boolean

conversationId

string

internetMessageId

string

Example

{
  "body": {
    "contentType": "text"
  },
  "from": {
    "emailAddress": {
      "name": "Jane Doe",
      "address": "jane@example.com"
    }
  },
  "toRecipients": [
    {
      "emailAddress": {
        "name": "Jane Doe",
        "address": "jane@example.com"
      }
    }
  ],
  "ccRecipients": [
    {
      "emailAddress": {
        "name": "Jane Doe",
        "address": "jane@example.com"
      }
    }
  ]
}

Headers

x-ms-request-id

string

Microsoft’s own request id for the upstream call. Quote this when raising an issue with Microsoft support. (Graph returns it as request-id; it is re-emitted under this name because Request-ID is already used for our own request identifier.)

401

Missing or invalid API key. Also returned when the key has been revoked.

application/json

OData error

Microsoft’s error shape, used on the /azure and /google surfaces so Graph SDKs deserialise failures as ordinary errors.

object

error

required

object

code

required

Microsoft’s error code for the status.

string

Allowed values: BadRequest InvalidAuthenticationToken ErrorAccessDenied ResourceNotFound RequestNotSupported RequestEntityTooLarge TooManyRequests UnknownError NotImplemented ServiceUnavailable Timeout

message

required

string

innerError

object

request-id

Correlation id for this request. Quote it in support requests.

string

date

string format: date-time

Example

{
  "error": {
    "code": "InvalidAuthenticationToken",
    "message": "The API key is invalid or has been revoked.",
    "innerError": {
      "request-id": "a26397a7-04e1-4c8f",
      "date": "2026-07-31T08:24:57+00:00"
    }
  }
}

403

The key is valid but not usable here: it is a Provisioning key rather than a Mailbox key, it is a sandbox key, or it is not linked to a sending.ac account.

application/json

OData error

Microsoft’s error shape, used on the /azure and /google surfaces so Graph SDKs deserialise failures as ordinary errors.

object

error

required

object

code

required

Microsoft’s error code for the status.

string

message

required

string

innerError

object

request-id

Correlation id for this request. Quote it in support requests.

string

date

string format: date-time

Example

{
  "error": {
    "code": "ErrorAccessDenied",
    "message": "The Mailbox API requires a live API key; sandbox keys are not accepted because these calls send and read real mail.",
    "innerError": {
      "request-id": "a26397a7-04e1-4c8f",
      "date": "2026-07-31T08:24:57+00:00"
    }
  }
}

404

Either the mailbox is not yours (or does not exist), or the Graph path is outside the allow-list. Both answer 404 so the API does not disclose which.

application/json

OData error

Microsoft’s error shape, used on the /azure and /google surfaces so Graph SDKs deserialise failures as ordinary errors.

object

error

required

object

code

required

Microsoft’s error code for the status.

string

message

required

string

innerError

object

request-id

Correlation id for this request. Quote it in support requests.

string

date

string format: date-time

Example

{
  "error": {
    "code": "ResourceNotFound",
    "message": "No such mailbox.",
    "innerError": {
      "request-id": "a26397a7-04e1-4c8f",
      "date": "2026-07-31T08:24:57+00:00"
    }
  }
}

429

Rate limit exceeded — 60 requests per minute per API key.

application/json

OData error

Microsoft’s error shape, used on the /azure and /google surfaces so Graph SDKs deserialise failures as ordinary errors.

object

error

required

object

code

required

Microsoft’s error code for the status.

string

message

required

string

innerError

object

request-id

Correlation id for this request. Quote it in support requests.

string

date

string format: date-time

Example

{
  "error": {
    "code": "TooManyRequests",
    "message": "Too many requests. Retry after the number of seconds in Retry-After.",
    "innerError": {
      "request-id": "a26397a7-04e1-4c8f",
      "date": "2026-07-31T08:24:57+00:00"
    }
  }
}

Headers

Retry-After

integer

Seconds to wait before retrying.

X-RateLimit-Limit

integer

X-RateLimit-Remaining

integer

X-RateLimit-Reset

integer

Unix timestamp at which the window resets.

502

Microsoft Graph could not be reached, or its response was too large to relay.

For sendMail this is ambiguous: the message may already have been accepted and sent. Do not retry automatically.

application/json

OData error

Microsoft’s error shape, used on the /azure and /google surfaces so Graph SDKs deserialise failures as ordinary errors.

object

error

required

object

code

required

Microsoft’s error code for the status.

string

message

required

string

innerError

object

request-id

Correlation id for this request. Quote it in support requests.

string

date

string format: date-time

Example

{
  "error": {
    "code": "UnknownError",
    "message": "Could not reach Microsoft Graph. The request may not have been processed; retry only if it is safe to repeat.",
    "innerError": {
      "request-id": "a26397a7-04e1-4c8f",
      "date": "2026-07-31T08:24:57+00:00"
    }
  }
}

503

The Mailbox API is temporarily unavailable, or credentials could not be verified. Safe to retry with backoff.

application/json

OData error

Microsoft’s error shape, used on the /azure and /google surfaces so Graph SDKs deserialise failures as ordinary errors.

object

error

required

object

code

required

Microsoft’s error code for the status.

string

message

required

string

innerError

object

request-id

Correlation id for this request. Quote it in support requests.

string

date

string format: date-time

Example

{
  "error": {
    "code": "BadRequest"
  }
}