OTP & Verification

Multi-channel OTP
99.9% success rate.

Send OTP via SMS, Voice, WhatsApp, or Flash Call. Automatic fallback ensures your users can always verify.

Start verifying usersView documentation
CanaryVerify Dashboard
Live
99.9%
Success
3s
Flash Call
4
Channels
SMS
98.5%8s
Voice
99.2%12s
Flash Call
99.8%3s
WhatsApp
99.5%5s
Verification that never failsVerification that never failsVerification that never failsVerification that never fails
Verification that never failsVerification that never failsVerification that never failsVerification that never fails

Features

Verification that never fails

01

Automatic Fallback

If SMS fails, automatically fall back to Voice, WhatsApp, or Flash Call. Never miss a verification.

SMS
Voice
Flash

Flash Call OTP

Instant verification using missed calls. No user input required. Zero friction.

3s
Average verification

99.9% Success

Multi-channel delivery ensures your users can always verify. Global coverage in 200+ countries.

Never miss a verification

Smart Routing

Intelligent routing based on user location and carrier. Optimize for cost and speed automatically.

US NumbersSMS First
IndiaFlash Call
LATAMWhatsApp

Integration

Verify users in seconds

02
verify-user.ts
// Start verification with fallback
import { Canary } from "@canary/sdk";
const canary = new Canary();
// Send OTP
const verify = await canary.verify.start({
to: "+15551234567",
channel: "sms",
fallback: ["voice", "whatsapp"]
});
// Check code
const result = await canary.verify.check({
id: verify.id,
code: "847291"
});

Multiple channels

SMS, Voice, WhatsApp, and Flash Call in one API

Auto fallback

Configurable fallback chain for maximum delivery

Fraud detection

Built-in protection against bots and fraud

Global coverage

Verify users in 200+ countries worldwide

FAQ

Common questions

03

What is Flash Call verification?

01

Flash Call sends a missed call to the user's phone with the verification code embedded in the caller ID. The user doesn't need to answer - the code is extracted automatically. It's fast, cheap, and has a 99.8% success rate.

How does automatic fallback work?

02

You configure a fallback chain (e.g., SMS → Voice → WhatsApp). If the primary channel fails or times out, we automatically try the next channel. This ensures maximum delivery rates.

Which channel should I use?

03

It depends on your users' location. SMS works well in the US, Flash Call is popular in India, and WhatsApp is preferred in Latin America. Our smart routing optimizes this automatically.

How do you prevent fraud?

04

We have built-in rate limiting, device fingerprinting, and bot detection. You can also set custom rules based on phone number, IP, or device to block suspicious verification attempts.

Ready to secure your users?

Get started with multi-channel OTP verification today.