Send SMS

{
  "recipient": "+255614853618",
  "message": "Hello, this is a test message",
  "sender_id": "MIFUMO"
}

{
  "success": true,
  "message": "SMS sent successfully",
  "data": {
    "message_id": "550e8400-e29b-41d4-a716-446655440000",
    "recipient": "+255614853618",
    "message": "Hello, this is a test message",
    "sender_id": "MIFUMO",
    "status": "queued",
    "cost": 0.05,
    "currency": "USD",
    "sent_at": "2025-11-27T10:30:00Z"
  }
}

{
  "success": false,
  "error": "Insufficient credits",
  "message": "You need 1 credit to send this message. Current balance: 0 credits",
  "required_credits": 1,
  "current_balance": 0
}