Quick Start

Send your first SMS in under 5 minutes.

1. Get your API credentials

API Key ID — used as the Basic Auth username
API Key Secret — used as the Basic Auth password

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Your Key Secret is shown only once at creation time. Store it securely — if lost, you'll need to generate a new key.

2. Verify your sender number

Every message must be sent from a phone number assigned to your account. Check your assigned numbers under Numbers in the dashboard. The number must be in Active state to send.

3. Send your first message

Make a POST request to the send message endpoint with Basic Auth:

curl -X POST https://platform.textingline.com/api/v1/messaging/message \
  -u "your_key_id:your_key_secret" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+18005551234",
    "from": "+18005559876",
    "body": "Hello from the Textingline API!"
  }'

A successful response looks like:

{
  "id": "msg_DsAdb4EBYBh3z25sBA1qnv",
	"direction": "outbound",  
  "to": "+18005551234",
  "from": "+18005559876",
  "body": "Hello from the Textingline API!",
  "status": "sent",
	"sentAt": "2026-03-15T14:30:05.000Z",  
  "createdAt": "2026-03-13T14:30:00.000Z"
}

Check the status field — sent or queued means the message was accepted. If status is failed, the response includes errorType and errorMessage describing why. See Send a Message for details.

4. Send an MMS (optional)

To send a picture message, add a mediaUrl field pointing to a publicly accessible image:

curl -X POST https://platform.textingline.com/api/v1/messaging/message \
  -u "your_key_id:your_key_secret" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+18005551234",
    "from": "+18005559876",
    "body": "Check this out!",
    "mediaUrl": "https://example.com/image.jpg"
  }'

Next steps

Send a broadcast to up to 50,000 recipients
Set up idempotency for safe retries
Explore the full API reference