Vonage (formerly Nexmo) provides a suite of communication APIs for building messaging, voice, and video features. Send SMS globally, make and receive programmatic voice calls with TTS and IVR flows, verify phone numbers via OTP, implement WebRTC video sessions, and manage virtual phone numbers. The Vonage Application API ties everything together under a single project.
https://rest.nexmo.com
Auth type
Basic Auth
Auth header
Authorization: Basic base64(api_key:api_secret)
Rate limit
30 messages/sec (SMS)
Pricing
from $0.01/mo
Free quota
$2 free credit on signup
Documentation
https://developer.vonage.com/en/api
Endpoint status
Server online — HTTP 404 — server is online but path returned an error (may require auth)904ms
(checked Mar 29, 2026)
Builder score
B
68%
builder-friendly
Use your API Key and API Secret as Basic Auth credentials, or generate JWTs for newer API endpoints.
Authorization: Basic base64(api_key:api_secret)
SMS: from $0.0079/message. Voice calls: from $0.0043/min. Number Insight: $0.005/lookup. Verify API: $0.055/successful verification. Phone number rental: $1–3/month.
| Method | Path | Description |
|---|---|---|
| POST | /sms/json |
Send an SMS message to any phone number |
| POST | /verify/json |
Send OTP verification code via SMS or voice |
| POST | /verify/check/json |
Verify the OTP code entered by the user |
| POST | /v1/calls |
Initiate an outbound voice call with NCCO flow |
| GET | /v1/account/numbers |
List virtual phone numbers in your account |
| GET | /ni/basic/json |
Number Insight — validate and look up a phone number |
curl "https://rest.nexmo.com/sms/json" \
-H "Content-Type: application/json" \
-d '{"api_key":"$VONAGE_API_KEY","api_secret":"$VONAGE_API_SECRET","to":"14155552671","from":"Vonage APIs","text":"Hello from Vonage!"}'
{
"message-count": "1",
"messages": [{
"to": "14155552671",
"message-id": "0C000000DA7CFAE5",
"status": "0",
"remaining-balance": "3.14159",
"message-price": "0.00570000",
"network": "310090"
}]
}
Data sourced from API Map. Always verify pricing and rate limits against the official Vonage documentation.