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Changelog

Prelude Documentation

Explore our guides and examples to implement Prelude, our powerful and easy-to-use API that lets you send OTP codes and transactional messages worldwide.

Overview

Understand how Prelude works to leverage its full potential.

How Prelude works

Learn how Prelude partners with multiple providers and channels to guarantee the highest possible delivery rate at the lowest possible cost.

Multi-Routing

Multi-Routing explained

Understand how Prelude's fraud prevention algorithm works, the type of fraud it prevents and how to configure it.

Anti-Fraud

Anti-Fraud explained

Monitor your performance and configure your integration with your Dashboard. To get access to the dashboard, you must first sign up and create an app.

Dashboard

The Prelude Dashboard

Learn how to use our client side iOS SDK.

iOS SDK

Learn how to use our client side Android SDK.

Android

Android SDK

Learn how to use our client side Expo React Native SDK.

React Native

React Native SDK

Learn how to capture front end browser signals to integrate them with the verification backend APIs. It allows you to capture certain browser signals that will be reported back to your Prelude account.

JS Signals

JavaScript Signals SDK

Node.js

Python

Kotlin/Java

Allow your users to onboard faster without the need for manually entering a verification code.

Integration

Silent Verification

GitHub

Manage the full lifecycle of your users' sessions.

Introduction

Prelude Session API

Learn how Prelude session applications work.

Applications

Session Applications

Learn about the cookies used by the Session API.

Cookies

Learn about the JWKS used by the Session API.

JWKS

JSON Web Key Set (JWKS)

Send and verify a code in 2 minutes and 3 simple steps with our SDKs, available for Node.js, Python, and Go.

Quickstart

Analytics

Analytics explained

Learn how to confirm that your integration is working properly by simulating OTPs without incurring charges using special test numbers.

Testing

Send OTPs to test your integration

Configure your integration to protect your application against fraud like SMS pumping or IRSF fraud with Prelude’s machine learning models.

Prevent Fraud

Learn how to use our iOS SDK. It allows you to capture certain device signals that will be reported back to Prelude.

Learn how to use our Android SDK. It allows you to capture certain device signals that will be reported back to Prelude.

Learn how to use our Expo React Native SDK. It allows you to capture certain device signals (both in Android and iOS) that will be reported back to Prelude.

Learn how to integrate the Prelude APIs and SDKs with other platforms.

Integrations

Everything you need to integrate the V2 API from any language and access our Verify, Transactional and Watch APIs and features.

Introduction to the V2 API

Everything you need to know about Prelude Transactional API to start sending transactional messages to your users via SMS and online messaging channels.

Introduction to the Transactional API

Prelude Transactional API can notify your application about events using webhooks. Get notified when your messages are delivered and billed.

Webhook

Webhook for the Transactional API

Integrate the Prelude Verify API from any language to start sending OTP messages to your users worldwide using multiple messaging channels.

Send OTP codes worldwide using the Verify API

Prelude Verify API can adapt your verification messages content for specific use cases.

Templates

Using Templates

Prelude Verify API can notify your application about events using webhooks. Get notified when your messages are delivered and billed.

Webhook for the Verify API

Identify trustworthy email addresses or phone numbers to mitigate both fake and fraudulent traffic.

Introduction to the Watch API

Learn how to troubleshoot errors like invalid custom code or unauthorized Sender ID to ensure a robust integration.

Errors

Troubleshooting errors

Introduction to the V1 API (Legacy)

This page presents how to handle errors with our Legacy API, V1.

Troubleshooting errors (V1 API)

This page presents how to send a code with our Legacy API, V1.

Send a code

Send a code (V1 API)

This page presents how to check a code with our Legacy API, V1.

Check a code

Check a code (V1 API)

This page presents how to perform a retry with our Legacy API, V1.

Perform a retry

Perform a retry (V1 API)

Send feedback

This page presents how to get authentication status with our Legacy API, V1.

Get authentication status

Get authentication status (V1 API)

Look up for phone number

Ruby

Java

Learn how to easily register a webhook with Prelude to get notified when your messages are delivered and billed.

Documentation

​May 2025

​April 2025

​March 2025

​February 2025

​January 2025

​December 2024

​November 2024