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Verify is a powerful and easy-to-use API that lets you verify phone numbers and email addresses worldwide using the most appropriate and depending on your user’s context. It manages the full verification lifecycle for you, from initiating the verification, sending OTP messages and performing retries, to checking the validity of the OTP code and returning the result. Businesses typically see a 20-30% increase in conversion compared with their previous provider, while saving 30-40% monthly. Prelude’s Verify API also detects and prevents fraud using algorithms trained on tens of millions of data points.

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Start a verification

2 min

Send and verify an OTP code in a few lines.

Get started →

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API

The Prelude v2 API is a REST API and uses standard HTTP features and statuses. The current URL is https://api.prelude.dev/v2.

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Authentication

To perform requests on the API, you need to provide a v2 API key in the Authorization header. You can create an API key in the Dashboard, under the API Keys section of the settings.
Example request
curl --request POST \
     --url 'https://api.prelude.dev/v2/*' \
     --header 'Accept: application/json' \
     --header 'Authorization: Bearer <API_KEY>'

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Errors

Prelude uses conventional HTTP statuses to indicate the success or failure of a request:
  • Codes in the 2xx range indicate success.
  • Codes in the 4xx range indicate an error that failed given the information provided (e.g. required parameter was omitted, authentication failed or a rate limit was reached).
  • Codes in the 5xx range indicate an error with Prelude's servers (these are rare).
The Prelude API returns errors using a JSON object in the response body with a machine-readable code and a human-readable message and a param field. See Errors for more details as well as a list of all possible error codes.

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API Reference

Explore the Verification API reference to learn more about the available endpoints:

Create/Retry Verification

Create a new verification session. If another non-expired verification exists perform a retry instead.

Check Verification Code

Check the validity of a code.

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Backend SDKs

Integrate effortlessly with Prelude using our Backend SDKs for your platform of choice.

Node.js

Learn how to integrate the Node.js SDK into your application.

Go

Learn how to integrate the Go SDK into your application.

Python

Learn how to integrate the Python SDK into your application.

Kotlin/Java

Learn how to integrate the Kotlin/Java SDK into your application.

Ruby

Learn how to integrate the Ruby SDK into your application.

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Frontend SDKs

Explore how you can enhance your verification process with our Frontend SDKs.

Android SDK

Learn how to integrate the Android SDK into your application.

iOS SDK

Learn how to integrate the iOS SDK into your application.

Web SDK

Learn how to integrate the Web SDK into your application.

React Native SDK

Learn how to integrate the React Native SDK into your application.

Flutter SDK

Coming soon. Will be available by the end of 2025.