ReOTP.
Fast-Track Integration 🚀

Zero-Delay
Authentication

Goodbye loading spinners. ReOTP is natively designed to provide a 0-second login experience by pre-fetching verification links in the background.

1. Predictive Init

While the user types their number, a silent request fetches the links without deducting balance.

2. Instant Redirect

When the user clicks login, they are redirected to WhatsApp instantly without waiting for a server response.

3. Status Polling

In the frontend, the code polls for verification success every 2 seconds until complete.

Optimized for AI Agents

Copy this prompt, and Cursor or Claude will generate the complete Zero-Delay Authentication code for you in seconds.

Comprehensive Documentation Index

Getting Started

Introduction to ReOTP

Learn how to integrate WhatsApp and Telegram OTP verification into your app.

Security

Rate Limiting & Anti-Spam

Understand the security protocols that protect your project.

API Reference

1. Pre-fetch Links in Background (Zero-Delay)

Secretly pre-fetch verification links with zero delay before the user clicks login.

2. Check Status

Query the status of the ongoing verification session.

Advanced Features

Webhooks Reference

Receive instant updates on verification events directly on your backend.

Channel Setup

Custom WhatsApp Linking

Send OTP verification messages from your own custom brand number.

SDKs & Libraries

ReOTP Node.js SDK

A ready-to-use library to simplify using ReOTP in Node.js/Next.js applications.

Security & Sync

Webhooks & HMAC Security

Learn how to receive secure, real-time notifications when a phone number is verified.

JWT Authentication

Using signed JWTs to securely authenticate the client.

Pricing & Billing

Smart Token Billing

How credits are automatically deducted based on the verification method.

Verification Methods

Passkeys (WebAuthn)

The next generation of passwordless authentication.

Integration Models

Standard 2FA

How to program classic two-factor authentication with high security for sensitive operations.

Passwordless Lite

How to integrate the fastest login method for Super Apps.

Smart 2FA + Biometric

Programming hybrid login to reduce cost and increase security.

Pure Passwordless

Eliminate passwords and messages to build a magical experience.

Tips

Pro Tips for Zero-Delay Integration

Learn the secrets and techniques used by top companies to integrate ReOTP for maximum speed and best UX.

Interactive Live API Playground

Test verification requests live and generate integration code in your preferred programming language.

curl -X POST https://reotp.com/api/verify/init \
  -H "Authorization: Bearer 15a1c1c7-ed05-40df-b7c3-69c327542a07" \
  -H "Content-Type: application/json" \
  -d '{
    "phoneNumber": "201000000000",
    "method": "WHATSAPP"
  }'