Verify / OTP & 2FA API
NobleStack's Verify API makes user authentication fast, reliable, and secure. Deliver one-time passwords and two-factor authentication across SMS, voice, and WhatsApp with a single integration — complete with automatic channel fallback so a legitimate user is never locked out.
One integration, complete verification
Instead of stitching together separate SMS, voice, and messaging systems, the Verify API handles the entire OTP lifecycle — code generation, delivery, retries, and validation — behind one endpoint. If an SMS is delayed, it automatically falls back to a voice call or WhatsApp message, keeping your conversion high and your users happy.
Capabilities
- OTP delivery across SMS, voice call, and WhatsApp
- Automatic channel fallback for maximum deliverability
- Server-side code generation, validation, and expiry management
- Configurable code length, format, and retry logic
- Rate limiting and fraud controls to block abuse
- Multi-language and regional-language OTP templates
- Real-time verification analytics and success-rate reporting
- Simple REST API and SDKs for rapid, secure integration
Why it matters
- Protect accounts and transactions from unauthorised access
- Reduce fraud and fake sign-ups with reliable phone verification
- Improve conversion with fast delivery and smart fallback
- Offload compliance and delivery complexity to NobleStack
Common scenarios
- Login and sign-up verification for apps and portals
- Transaction and payment confirmation for fintech and e-commerce
- Password resets and sensitive-action approvals
- Account-recovery and identity re-verification flows
How it works
From verification request to confirmed user
One API for OTP and 2FA across SMS, voice, and WhatsApp — with fallback logic so a legitimate user is never locked out by one failed channel.
Request
Ask for a verification
Call the API with the user's number and preferred channel. We generate, send, and store the code — you never handle secrets or expiry logic.
Fallback
Escalate channels automatically
If SMS is not delivered in time, the same verification retries over voice or WhatsApp before it expires, without a second integration.
Check
Validate in one call
Submit the code the user entered and get a definitive result, with attempt limits, expiry, and rate limiting enforced on our side.
Tune
Watch conversion, not just delivery
Per-channel success rates, time-to-verify, and drop-off data show where users fail so you can adjust channel order and timeouts.
99.95%
Platform uptime SLA
7Cr+
Daily OBD handled
500+
Businesses onboarded
24×7
Engineering support
Talk to us
Talk to our team about what you are building
Tell us the workflow you have in mind and the scale you expect. Our solutions team maps it to the right NobleStack setup, flags anything that needs a custom approach, and sends you pricing for your volume — no obligation.
Same-day response
Weekday enquiries get a reply within business hours.
A specialist, not a script
You speak to someone who has actually shipped this kind of setup.
Compliance answers upfront
Consent, data residency, retention, and audit questions covered early.