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POST
Create a mailbox

Authorizations

Authorization
string
header
required

Sendmux API key. Use a root API key for Management API routes, or a mailbox credential for Mailbox API routes. Obtain keys from the dashboard under API Keys.

Headers

Idempotency-Key
string

Client-chosen unique key to safely retry the request. Cached for 24h per (team, endpoint, key). Different body with same key returns 409 idempotency_conflict.

Maximum string length: 255
Example:

"mailboxes-create-20260424-001"

Body

application/json
email
string
required

Mailbox email address to create.

Required string length: 5 - 254
display_name
string

Optional display name shown in outbound From headers.

Required string length: 1 - 254
quota_bytes
integer

Storage quota in bytes. Allowed values: 1073741824 (1 GB), 5368709120 (5 GB), 53687091200 (50 GB).

Required range: x >= 1
Example:

5368709120

send_scope
object

Optional outbound routing restrictions.

Response

Mailbox created. The response carries a Location header pointing at the canonical GET URL for the new mailbox.

meta
object
required
ok
enum<boolean>
required
Available options:
true
data
object
required