API Authentication — Bearer Token Guide

All requests to the MigoSMTP and Telnxo APIs are authenticated using a Bearer token — your API key passed in the HTTP Authorization header. This article explains the exact format required, shows code examples in multiple languages, and covers how to handle authentication errors.

The Authorization Header

Every API request must include the following HTTP header:

Authorization: Bearer YOUR_API_KEY_HERE

Code Examples

cURL

curl -X POST https://api.migosmtp.com/v1/email/send 
  -H "Authorization: Bearer YOUR_API_KEY" 
  -H "Content-Type: application/json" 
  -d '{
    "from": "hello@yourdomain.com",
    "to": "recipient@example.com",
    "subject": "Hello from MigoSMTP",
    "html": "<p>Your message here</p>"
  }'

PHP (using cURL)

$apiKey = getenv('MIGOSMTP_API_KEY');

$ch = curl_init('https://api.migosmtp.com/v1/email/send');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Authorization: Bearer ' . $apiKey,
    'Content-Type: application/json',
]);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode([
    'from'    => 'hello@yourdomain.com',
    'to'      => 'recipient@example.com',
    'subject' => 'Hello from MigoSMTP',
    'html'    => '<p>Your message here</p>',
]));

$response = curl_exec($ch);
$data = json_decode($response, true);
curl_close($ch);

Python (using requests)

import os
import requests

api_key = os.environ.get('MIGOSMTP_API_KEY')

response = requests.post(
    'https://api.migosmtp.com/v1/email/send',
    headers={
        'Authorization': f'Bearer {api_key}',
        'Content-Type': 'application/json',
    },
    json={
        'from': 'hello@yourdomain.com',
        'to': 'recipient@example.com',
        'subject': 'Hello from MigoSMTP',
        'html': '<p>Your message here</p>',
    }
)

data = response.json()

Node.js (using fetch)

const apiKey = process.env.MIGOSMTP_API_KEY;

const response = await fetch('https://api.migosmtp.com/v1/email/send', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${apiKey}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    from: 'hello@yourdomain.com',
    to: 'recipient@example.com',
    subject: 'Hello from MigoSMTP',
    html: '<p>Your message here</p>',
  }),
});

const data = await response.json();

Telnxo SMS (cURL)

curl -X POST https://api.telnxo.com/v1/sms/send 
  -H "Authorization: Bearer YOUR_TELNXO_API_KEY" 
  -H "Content-Type: application/json" 
  -d '{
    "from": "YOURBRAND",
    "to": "+919876543210",
    "message": "Your OTP is 482910. Valid for 10 minutes."
  }'

Authentication Error Responses

Common Authentication Mistakes

• Using the wrong platform key — using a MigoSMTP key on the Telnxo API endpoint returns a 401 error. Check you are using the key generated for the correct platform.
• Extra whitespace in the key — copying a key with a trailing space or newline character causes authentication to fail. Trim your key value before storing it.
• Using the key as a query parameter — some legacy APIs accept keys via URL query string. Rackwave APIs do not. Always use the Authorization header.
• Omitting the Bearer prefix — sending just the key without the Bearer prefix returns a 401 error.

Next Steps

• Understanding rate limits & throttling
• API error codes reference
• Send email API — endpoint reference
• SMS Send API — endpoint reference