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Mailbox API

List mail folders

GET
/azure/v1.0/users/{email}/mailFolders
curl --request GET \
  --url https://api.customers.ac/api/mailbox/v1alpha1/azure/v1.0/users/sender%40yourdomain.com/mailFolders \
  --header 'Authorization: Bearer <token>'

Lists the mailbox’s folders. Mirrors Graph’s GET /users/{id}/mailFolders.

Use this to discover folder ids and to read totalItemCount / unreadItemCount without pulling messages.

Authorizations

Section titled “Authorizations”

Parameters

Section titled “Parameters”

Path Parameters

Section titled “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

Responses

Section titled “Responses”

200

Section titled “200”

A page of mail folders.

Media typeapplication/json
object
value
Array<object>
object
id
string
displayName
string
parentFolderId
string
childFolderCount
integer
unreadItemCount
integer
totalItemCount
integer
@odata.nextLink
string format: uri
Example
{
  "value": [
    {
      "displayName": "Inbox"
    }
  ]
}

Headers

Section titled “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

Section titled “401”

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 Also returned when the key has been revoked.

Media typeapplication/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    "message": "The API key is invalid or has been revoked.",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

Section titled “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.

Media typeapplication/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": "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

Section titled “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.

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

429

Section titled “429”

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

Media typeapplication/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": "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

Section titled “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

Section titled “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.

Media typeapplication/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": "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

Section titled “503”

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

Media typeapplication/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": "BadRequest"
  }
}