How do I integrate it?

Create an API key in the dashboard, then call the REST endpoints from your backend. Auth is an x-api-key header. No SDK required — curl, fetch, or any HTTP client works.

What is the difference between test and live keys?

pk_test_ keys never send SMS. A random code appears in the dashboard Test OTP inbox — copy it and verify with the API. pk_live_ keys send a real SMS. Use test keys in local and CI.

Can I use this for web and mobile?

Yes. Keep the API key on your server and call send/verify from there. Web, iOS, and Android can share the same backend.

What happens after the code is verified?

You can stop there, or pass the verification_id to /v1/auth/signup or /v1/auth/login. Those return JWT access and refresh tokens for that phone.

How is pricing calculated?

Starter includes 50 free OTPs per account, shared across apps. Growth is ₹499/month for 1,500 OTPs. Extra volume is pay as you go from ₹0.32 per OTP. Test keys never send SMS.

Free 50 OTPs · No Card Needed

India's Fastest Way to Add Phone Verification

Send a code, verify it, issue a session. Two API calls.

Get API key

OTP demo

Send a code, enter it, get verified.

Test key

User Phone Number

Test mode • no SMS

Click "Send Verification Code" to test

FlashAuth OTP

Your app. Our OTP layer. Their phone.

We sit between your backend and SMS. You never talk to the provider directly.

See how it works

1. Your app

API key

Call /v1/otp/send with an E.164 phone number.

2. FlashAuth → SMS

Provider

Live keys send the OTP. Test keys skip SMS entirely.

3. User enters the code

5 min

Codes expire in 5 minutes. Resend waits 30 seconds.

4. You get the result

verified

Verify the code, then sign up or log in with the verification_id.

The product

Everything you need for phone OTP

Send, verify, and issue a session. The rest stays in the dashboard.

The OTP layer, not another SMS console

Integrate once. Manage keys, usage, and users from the dashboard.

See pricing

SMS

Phone OTP

Send and verify SMS codes with two HTTP calls.

Auth

API keys

pk_test_ for local work. pk_live_ for production SMS.

Sandbox

Test mode

No SMS is sent. copy the code from the dashboard inbox.

Built-in

Abuse limits

30s resend cooldown, 5-minute expiry, attempt caps.

JWT

Sessions

Signup and login return JWT access and refresh tokens.

Control

Dashboard

Keys, usage, users, and SMS copy in one place.

How it works

Three calls. Phone auth is done.

Key, send, verify. Optional signup and login if you want sessions.

Create an API key

Dashboard

Test keys start with pk_test_. Live keys start with pk_live_.

Send the OTP

POST send

POST /v1/otp/send with the user's phone number in E.164.

Verify and continue

POST verify

POST /v1/otp/verify, then signup or login with the verification_id.

Works from any HTTP clientGet API key

API key created

Step 01

pk_test_… skips SMS. pk_live_… sends a real OTP.

Auth: x-api-keyCopy code from dashboard

Where it fits

Drop it into the flows you already have

Same API for sign-up, login, and recovery — web or mobile.

New users

SaaS sign-up

Verify the phone before you create the account.

Returning

Login

Passwordless sign-in with a one-time SMS code.

Confirm

Phone verification

Prove a number belongs to the person in the flow.

New users

SaaS sign-up

Verify the phone before you create the account.

Returning

Login

Passwordless sign-in with a one-time SMS code.

Confirm

Phone verification

Prove a number belongs to the person in the flow.

New users

SaaS sign-up

Verify the phone before you create the account.

Returning

Login

Passwordless sign-in with a one-time SMS code.

Confirm

Phone verification

Prove a number belongs to the person in the flow.

New users

SaaS sign-up

Verify the phone before you create the account.

Returning

Login

Passwordless sign-in with a one-time SMS code.

Confirm

Phone verification

Prove a number belongs to the person in the flow.

Reset

Account recovery

Send a code when email reset isn’t enough.

iOS / Android

Mobile apps

Call the same REST endpoints from native clients.

Browser

Web apps

Keep send and verify on your backend. Never expose live keys.

Reset

Account recovery

Send a code when email reset isn’t enough.

iOS / Android

Mobile apps

Call the same REST endpoints from native clients.

Browser

Web apps

Keep send and verify on your backend. Never expose live keys.

Reset

Account recovery

Send a code when email reset isn’t enough.

iOS / Android

Mobile apps

Call the same REST endpoints from native clients.

Browser

Web apps

Keep send and verify on your backend. Never expose live keys.

Reset

Account recovery

Send a code when email reset isn’t enough.

iOS / Android

Mobile apps

Call the same REST endpoints from native clients.

Browser

Web apps

Keep send and verify on your backend. Never expose live keys.

Pricing

Start free. Pay when you send.

50 free OTPs per account. Growth is ₹499/month. Extra volume from ₹0.32 per OTP.

Starter

Free

Enough to integrate and send your first live OTPs.

₹0/ 50 OTPs

50 free OTPs per account
Production Keys
Send, verify, sessions

Get API key

Growth₹499/mo

For production traffic. Extra OTPs from ₹0.32.

₹499/ month

1,500 OTPs / month
Pay as you go from ₹0.32 / OTP
Dashboard usage and users

Get API key

Questions

Integration, keys, sessions, and pricing.

POST /v1/otp/send with a phone number. We deliver the SMS (or skip it on test keys). The user enters the code. POST /v1/otp/verify. You get back verified: true and a verification_id.

Start with a test key

Create an account, grab pk_test_, and copy the code from the dashboard inbox. No SMS required.

Get API key See the API