Compare the best free SMS APIs and Twilio alternatives: Vonage, Plivo, MessageBird, TextBelt. Code examples for sending SMS via REST API.
Sending text messages from your application is one of the most effective ways to reach users. SMS has a 98% open rate compared to 20% for email, and 90% of messages are read within three minutes. In 2026, a free SMS API lets you send transactional messages, OTP codes, and notifications without the steep per-message costs of traditional providers.
If you have been searching for a Twilio alternative that does not require a $20 minimum balance or charge $0.0079 per message, this guide compares the best free SMS API options available today with working code examples.
An SMS API is a programmatic interface that lets you send and receive text messages through HTTP requests. Instead of manually sending texts or using a desktop application, your code makes API calls that trigger SMS delivery to any mobile phone number worldwide.
Modern SMS APIs handle the complexity of carrier routing, number formatting, delivery receipts, and regulatory compliance behind a simple REST endpoint. You send a POST request with the recipient number and message body, and the API handles everything else.
Integrating an SMS API into your application provides measurable benefits over email and push notifications:
The challenge has always been cost. Twilio charges $0.0079 per outbound SMS in the US, plus $1.15/month per phone number. For a startup sending 50,000 messages per month, that is $395 in messaging costs alone. Free SMS APIs eliminate or drastically reduce this cost.
The DevProToolkit API Hub includes an SMS endpoint that lets you send text messages to numbers worldwide. The free tier includes a generous monthly allowance and does not require a phone number purchase.
Offers a free trial with a small credit balance. After the trial, pricing starts at $0.0068 per message. Requires phone number verification and has a more complex setup process than simpler alternatives.
An open-source SMS API that offers 1 free text per day. Useful for testing but not practical for production usage. Paid plans start at $5 for 200 texts. Limited to US numbers on the free tier.
Provides a free trial with a small balance. After the trial, pricing is competitive at ~$0.0069 per message. Supports SMS, MMS, email, and fax through a unified API.
# Send an SMS message
curl -X POST "https://api.commandsector.in/api/sms/send" \
-H "X-API-Key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"to": "+1234567890",
"message": "Your verification code is 847291. It expires in 10 minutes."
}'Response:
{
"success": true,
"message_id": "msg_a8f3k29d",
"to": "+1234567890",
"status": "queued",
"segments": 1,
"cost": 0
}curl -X POST "https://api.commandsector.in/api/sms/send" \
-H "X-API-Key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"to": "+1234567890", "message": "Hello from the SMS API!"}'# Generate and send a one-time password
curl -X POST "https://api.commandsector.in/api/sms/otp" \
-H "X-API-Key: YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"to": "+1234567890",
"length": 6,
"expiry_minutes": 10,
"template": "Your login code is {otp}. Valid for {expiry} minutes."
}'# Check delivery status of a sent message
curl "https://api.commandsector.in/api/sms/status/msg_a8f3k29d" \
-H "X-API-Key: YOUR_API_KEY"import requests
API_KEY = "YOUR_API_KEY"
BASE_URL = "https://api.commandsector.in/api"
def send_sms(to, message):
"""Send an SMS message using the free SMS API."""
response = requests.post(
f"{BASE_URL}/sms/send",
headers={
"X-API-Key": API_KEY,
"Content-Type": "application/json"
},
json={
"to": to,
"message": message
}
)
response.raise_for_status()
return response.json()
def send_otp(phone_number, length=6, expiry=10):
"""Generate and send an OTP code via SMS."""
response = requests.post(
f"{BASE_URL}/sms/otp",
headers={
"X-API-Key": API_KEY,
"Content-Type": "application/json"
},
json={
"to": phone_number,
"length": length,
"expiry_minutes": expiry
}
)
response.raise_for_status()
return response.json()
# Send a transactional message
result = send_sms("+1234567890", "Your order #12345 has shipped!")
print(f"Message ID: {result['message_id']}, Status: {result['status']}")
# Send an OTP for two-factor authentication
otp_result = send_otp("+1234567890")
print(f"OTP sent. Verification ID: {otp_result['message_id']}")const API_KEY = 'YOUR_API_KEY';
const BASE_URL = 'https://api.commandsector.in/api';
async function sendSMS(to, message) {
const response = await fetch(`${BASE_URL}/sms/send`, {
method: 'POST',
headers: {
'X-API-Key': API_KEY,
'Content-Type': 'application/json'
},
body: JSON.stringify({ to, message })
});
if (!response.ok) {
throw new Error(`SMS send failed: ${response.statusText}`);
}
return response.json();
}
async function sendOTP(phoneNumber, length = 6) {
const response = await fetch(`${BASE_URL}/sms/otp`, {
method: 'POST',
headers: {
'X-API-Key': API_KEY,
'Content-Type': 'application/json'
},
body: JSON.stringify({
to: phoneNumber,
length: length,
expiry_minutes: 10
})
});
return response.json();
}
// Express.js middleware for SMS verification
app.post('/api/verify-phone', async (req, res) => {
const { phoneNumber } = req.body;
try {
const result = await sendOTP(phoneNumber);
// Store verification ID in session
req.session.verificationId = result.message_id;
res.json({ success: true, message: 'OTP sent' });
} catch (error) {
res.status(500).json({ error: 'Failed to send OTP' });
}
});
// Send order confirmation
sendSMS('+1234567890', 'Your order #789 is confirmed. Estimated delivery: March 3.')
.then(result => console.log('Sent:', result.message_id))
.catch(err => console.error('Error:', err.message));SMS-based OTP remains the most widely used second factor for login security. Send a 6-digit code to the user's phone during login, password reset, or high-value transactions. SMS OTP has higher completion rates than app-based authenticators because it requires no additional app installation.
Keep customers informed with real-time updates: order confirmation, payment received, item shipped, out for delivery, and delivered. E-commerce platforms that implement SMS order tracking see 25% fewer "where is my order?" support tickets.
Healthcare providers, salons, and service businesses reduce no-shows by 30-45% by sending SMS reminders 24 hours before appointments. Include a reply-to-confirm or reply-to-cancel option for interactive scheduling.
Send critical system alerts to on-call engineers. When your monitoring system detects downtime, trigger an SMS to the team immediately. SMS delivery does not depend on internet connectivity or app availability like Slack or PagerDuty push notifications.
Flash sales, limited-time promotions, and event reminders reach users instantly. SMS marketing campaigns see 10-15x higher engagement than email campaigns. Always ensure users have explicitly opted in to receive marketing messages.
No credit card, no phone number purchase. Get your API key and start sending messages in minutes.
Get Free API Key| Feature | DevProToolkit | Twilio | Vonage | TextBelt |
|---|---|---|---|---|
| Free Tier | Yes | Trial only | Trial only | 1/day |
| Credit Card Required | No | Yes | Yes | No |
| Per-Message Cost | Free tier | $0.0079 | $0.0068 | $0.025 |
| OTP Built-In | Yes | Verify add-on | Verify add-on | No |
| Global Coverage | 200+ countries | 180+ countries | 200+ countries | US only (free) |
Yes. DevProToolkit offers a free tier that includes SMS sending without requiring a credit card or phone number purchase. TextBelt also offers 1 free SMS per day for testing. Most other providers (Twilio, Vonage) offer trial credits but require payment information.
For developers looking for a free Twilio alternative, DevProToolkit provides SMS sending with a free tier, no credit card requirement, and built-in OTP support. The API is simpler to integrate — a single POST request to send a message versus Twilio's more complex account setup with SID, auth token, and phone number provisioning.
Yes. DevProToolkit supports sending SMS to 200+ countries on the free tier. Rates and delivery reliability vary by country. Tier 1 countries (US, UK, Canada, Australia) have the highest delivery rates.
Use the dedicated OTP endpoint. Send a POST request with the phone number, desired code length, and expiry time. The API generates a random code, sends it via SMS, and returns a verification ID. Use the verification ID to confirm the code the user enters.
The DevProToolkit free tier allows a generous number of messages per month. Rate limiting prevents abuse and ensures delivery quality. For high-volume senders, paid plans offer increased throughput and dedicated sending numbers.
No. Unlike Twilio and Vonage which require you to purchase a sending number ($1-2/month), DevProToolkit handles sender routing automatically. Your messages are sent from shared numbers optimized for delivery in each region.
Get your free API key and start making requests in minutes.
curl "http://147.224.212.116/api/..." \
-H "X-API-Key: YOUR_API_KEY"Get a free API key with 100 requests/day. No credit card required.
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