How to Send SMS

Bulkit SMS API lets you send one-off or multi-recipient SMS traffic from your own systems using your approved sender IDs and available account balance.

Use the SMS API when you need to:

• send transactional alerts
• send account or workflow notifications
• trigger system-generated outbound SMS
• schedule a message for later delivery

Endpoints

The main SMS send route documented in this section is:

POST /api/v2/messages/sms/bulk

Authorization

Bulkit v2 authenticates SMS requests using a single API token:

• Bearer Token (Recommended): Authorization: Bearer <your_api_token>
• Header Authorization
• URL Authorization

What you need before sending SMS

Before calling the SMS API, make sure you have:

• an active Bulkit account
• a valid API token
• enough credit on your account
• a valid sender ID assigned to your account
• recipient numbers in a supported Kenyan mobile format

Supported sending patterns

Bulkit currently supports:

• single-recipient SMS
• bulk SMS to multiple recipients
• scheduled SMS using timezone-aware timestamps

Important delivery constraints

Bulkit validates several common error conditions before accepting a request. Common API errors include:

• Invalid credentials
• Insufficient balance
• Invalid number
• Invalid sender ID
• Invalid message
• Restricted send time

Restricted promotional send time

If you schedule a promotional message to a Safaricom number outside that window, the request will be rejected with:

{
  "status": "error",
  "message": "Restricted send time"
}

Choose a send flow

• Send SMS Using Header Authorization
• Send SMS Using URL Params
• Send a Single SMS
• Send Bulk SMS
• Send SMS to Contacts
• Send Customized SMS

Webhooks and reporting

After sending SMS, you can continue with:

• How to Setup SMS Webhook
• How to Get Delivery Reports
• SMS API Error Messages

Error response

Typical validation failures use this format:

{
  "status": "error",
  "message": "Invalid credentials"
}