Test OTP delivery before you integrate
Use your free credits in the PIE Playground to send a real OTP, inspect the selected route and verify the code you receive. About the playground
Open the playground →
OTP delivery & verification API
OTP Verification. Smarter, Faster, More Affordable.
Reduce authentication costs with intelligent routing, multi-channel delivery, and automatic fallback. One API for SMS, WhatsApp, Viber, and RCS.
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whatsapp · delivered 1.6s
Trusted by global companies
Price intelligence engine
Lower your OTP delivery costs with automatic routing
SecondFactor selects the lowest-cost eligible route for each request and handles fallback as your app reaches users across different markets.
Cost-based selection
Route each OTP on destination pricing and the channels available to your account and your recipient.
Learn more →Automatic fallback
The next eligible channel is attempted when delivery isn't confirmed within eight seconds.
Learn more →Delivery logs and costs
See channel, status and cost per request to monitor spend and investigate failures.
Learn more →Authentication templates
Create OTP templates per connected channel and track approval status in one dashboard.
Learn more →
Integration
Two API calls. Every channel.
Let SecondFactor generate, send and verify your codes while your application handles the signup or login experience.
1
Send an OTP
Post the user's phone number to /Verifications to send a code through an eligible channel and receive a verification SID.
2
Verify the code
Post the verification SID and the code your user entered to /VerificationCheck to receive the verification result.
2
API calls to go live
4
Channels, one integration
8s
Fallback window
0
Codes stored in your app
Channels
Connect your OTP channels through one API
Enable the channels you need and let SecondFactor manage delivery without separate integrations in your application.
Number check · PASSEDRoute selection · LOWEST COSTTemplate · APPROVED
SMS OTP
Reach any mobile number without requiring a messaging app.
Explore →WhatsApp OTP
Deliver codes through your connected WhatsApp Business Account.
Explore →Viber OTP
Reach Viber users in supported markets via an approved business sender.
Explore →RCS OTP
Deliver codes to users whose devices and carriers support RCS.
Explore →Channel availability depends on the destination, recipient capabilities and completed sender approvals.
PIE Playground
Route inspector
- Attempt 1WhatsApp — no confirmation
- +8.0sFallback triggered automatically
- Attempt 2SMS — delivered 2.1s · $0.0071
- Verify200 OK · code matched
Add OTPs to your app
Build phone verification into signup or add a second authentication step with an API that handles code generation, delivery and verification.
Start building →Reduce your delivery costs
Explore lower-cost channels for your destination markets and manage routing, fallback and spending through one platform.
View pricing
Clients
Testimonials
See what teams building with SecondFactor say.
“Across ASEAN, every market has its own SMS rules and carriers. SecondFactor put routing, delivery and monitoring in one place — we don’t manage any of it separately anymore.”
“Our banks and merchants won’t tolerate a failed OTP at checkout. SecondFactor has been the verification layer behind our fintech integrations through every rollout.”
“Reaching our clients’ end users internationally is the hard part — carriers, delivery rates, compliance. SecondFactor handles that, and delivery stays solid.”
“I didn’t want to burn a week wiring up OTP for a side project. Plugged in SecondFactor, tested it and shipped the same day.”
How does SecondFactor choose a delivery channel?+
The Price Intelligence Engine checks the destination and eligible channels, then attempts delivery through the lowest-cost option. If delivery isn't confirmed within eight seconds, it tries the next eligible channel.
Do I need to connect every channel?+
You can start with the channels you need and add others later. SecondFactor routes requests through channels enabled for your account and available to the recipient.
Do I need a WhatsApp Business Account to send WhatsApp OTPs?+
Yes. You need to connect a WhatsApp Business Account and complete the applicable setup and authentication template approvals before sending WhatsApp OTPs.
Do I need to generate and store OTPs in my application?+
No. SecondFactor handles code generation and verification. Call the Verifications endpoint to send a code and VerificationCheck to check the code your user entered.
Can I test SecondFactor before going live?+
New accounts receive free credits to test real OTP delivery in the PIE Playground, inspect the selected route and verify the code received.
Can I see whether an OTP was delivered?+
Your dashboard includes OTP logs showing the destination, delivery channel, status and cost of each request.