v1 · API reference

SMS

Beta. Send transactional and marketing SMS, and track each message's delivery lifecycle. Marketing sends require recipient consent and honor recipient-local quiet hours. Returns `not_found` on workspaces where the channel isn't enabled yet.

Base URL: https://www.unitpost.com/api/v1

SMS

List SMS messages

GET/api/v1/sms

GET /sms

curl -X GET 'https://www.unitpost.com/api/v1/sms' \
  -H 'Authorization: Bearer YOUR_API_KEY'

Response · 200

{
  "object": "list",
  "has_more": false,
  "data": [
    {
      "object": "sms",
      "id": "id_123",
      "to": "customer@example.com",
      "from": "you@yourdomain.com",
      "direction": "outbound",
      "status": "queued",
      "type": "transactional",
      "body": "string",
      "segments": 0,
      "country": "string",
      "scheduled_at": "2026-01-01T00:00:00.000Z",
      "last_error": "string",
      "created_at": "2026-01-01T00:00:00.000Z"
    }
  ]
}

Retrieve your workspace's SMS messages (outbound and inbound), newest-first and cursor-paginated. Use a message's id with Retrieve an SMS message to read its delivery state. Requires the sms:read capability.

Parameters3 fields

Field	Type	Description
`limit`	integer · query	Max rows to return (default 20, max 100).
`after`	string · query	Return rows after this id (forward paging).
`before`	string · query	Return rows before this id (backward paging).

Response · 200 fields13 fields

Field	Type	Description
`object`required	string	—
`id`required	string	—
`to`required	string	—
`from`required	object	—
`direction`required	enumoutbound \| inbound	—
`status`required	enumqueued \| scheduled \| sending \| sent \| delivered \| failed \| suppressed \| canceled \| received	—
`type`required	enumtransactional \| marketing	—
`body`required	object	—
`segments`required	integer	—
`country`required	object	—
`scheduled_at`required	object	—
`last_error`required	object	—
`created_at`required	string	—

200401403422

Send an SMS message

POST/api/v1/sms

POST /sms

curl -X POST 'https://www.unitpost.com/api/v1/sms' \
  -H 'Authorization: Bearer YOUR_API_KEY' \
  -H 'Content-Type: application/json' \
  -d '{ }'

Response · 200

{
  "object": "sms",
  "id": "id_123",
  "to": "customer@example.com",
  "from": "you@yourdomain.com",
  "direction": "outbound",
  "status": "queued",
  "type": "transactional",
  "body": "string",
  "segments": 0,
  "country": "string",
  "scheduled_at": "2026-01-01T00:00:00.000Z",
  "last_error": "string",
  "created_at": "2026-01-01T00:00:00.000Z"
}

Send a single SMS — now, or at a future time by passing scheduled_at. The recipient must be a valid E.164 number; marketing sends additionally require the recipient's prior express consent on record and honor recipient-local quiet hours (they are deferred to the next allowed window, never dropped). Billing is per segment. Read delivery state back with Retrieve an SMS message. Requires the sms:send capability.

Request body4 fields

Field	Type	Description
`to`required	string	Recipient phone number in E.164 format, e.g. `+15551234567`.
`body`required	string	Message text. Billing is per segment (160 GSM-7 chars single-segment, 153 per segment concatenated; 70/67 for Unicode).
`type`	enumtransactional \| marketing	Marketing sends require the recipient's prior express consent on record and honor recipient-local quiet hours.
`scheduled_at`	string	ISO-8601 time to send at. Omit to send immediately.

Response · 200 fields13 fields

Field	Type	Description
`object`required	string	—
`id`required	string	—
`to`required	string	—
`from`required	object	—
`direction`required	enumoutbound \| inbound	—
`status`required	enumqueued \| scheduled \| sending \| sent \| delivered \| failed \| suppressed \| canceled \| received	—
`type`required	enumtransactional \| marketing	—
`body`required	object	—
`segments`required	integer	—
`country`required	object	—
`scheduled_at`required	object	—
`last_error`required	object	—
`created_at`required	string	—

200401403422429

Retrieve an SMS message

GET/api/v1/sms/{id}

GET /sms/{id}

curl -X GET 'https://www.unitpost.com/api/v1/sms/123' \
  -H 'Authorization: Bearer YOUR_API_KEY'

Response · 200

{
  "object": "sms",
  "id": "id_123",
  "to": "customer@example.com",
  "from": "you@yourdomain.com",
  "direction": "outbound",
  "status": "queued",
  "type": "transactional",
  "body": "string",
  "segments": 0,
  "country": "string",
  "scheduled_at": "2026-01-01T00:00:00.000Z",
  "last_error": "string",
  "created_at": "2026-01-01T00:00:00.000Z"
}

Retrieve one SMS message's current status, delivery state, and segment count by id. Requires the sms:read capability.

Parameters1 field

Field	Type	Description
`id`required	string · path	The SMS message id (`sms_…`).

Response · 200 fields13 fields

Field	Type	Description
`object`required	string	—
`id`required	string	—
`to`required	string	—
`from`required	object	—
`direction`required	enumoutbound \| inbound	—
`status`required	enumqueued \| scheduled \| sending \| sent \| delivered \| failed \| suppressed \| canceled \| received	—
`type`required	enumtransactional \| marketing	—
`body`required	object	—
`segments`required	integer	—
`country`required	object	—
`scheduled_at`required	object	—
`last_error`required	object	—
`created_at`required	string	—

200401403404