OAuth Social Login Guide | Backend SDK

This guide is meant for developers that are NOT using Descope on the frontend to design login screens and authentication methods.

If you'd like to use Descope Flows, Quick Start should be your starting point. If you'd like to use our Client SDKs, refer to our Client SDK docs.

To get started with authentication using Social Login (OAuth), refer to our Social Login Documentation. Continue reading to learn how to integrate Social Login into your application using our Backend SDKs.

Backend SDK

Install SDK

Terminal

npm i --save @descope/node-sdk

Import and initialize SDK

import DescopeClient from '@descope/node-sdk';
try{
    //  baseUrl="<URL>" // When initializing the Descope client, you can also configure the baseUrl ex: https://auth.company.com  - this is useful when you utilize a custom domain within your Descope project.
    const descopeClient = DescopeClient({ projectId: '__ProjectID__' });
} catch (error) {
    // handle the error
    console.log("failed to initialize: " + error)
}

Start OAuth

To initiate the OAuth process, call the OAuth initiation function after the user clicks the social login button. This function returns a pre-formatted URL that the client can use to redirect the user and begin the login flow with the selected Identity Provider (e.g., Google, Facebook, Microsoft).

// Args:
//   provider: social identity provider for authenticating the user. Supported values include "facebook", "github", "google", "microsoft", "gitlab" and "apple". The current list can be found at https://github.com/descope/core-js-sdk/blob/main/src/sdk/oauth/types.ts in the OAuthProviders array.
const provider = "facebook"
//   redirect_url: URL to return to after successful authentication with the social identity provider. You need to implement this page to access the token and finish oauth process (token exchange). The token arrives as a query parameter named 'code'.
const redirect_url = "https://auth.company.com/token_exchange"
//    loginOptions (LoginOptions): this allows you to configure behavior during the authentication process.
const loginOptions = {
      "stepup": false,
      "mfa": false,
      "customClaims": {"claim": "Value1"},
      "templateOptions": {"option": "Value1"}
    }
//    refreshToken (optional): the user's current refresh token in the event of stepup/mfa
 
const resp = await descopeClient.oauth.start[provider](redirect_url, loginOptions);
if (!resp.ok) {
  console.log("Failed to start oauth")
  console.log("Status Code: " + resp.code)
  console.log("Error Code: " + resp.error.errorCode)
  console.log("Error Description: " + resp.error.errorDescription)
  console.log("Error Message: " + resp.error.errorMessage)
}
else {
  const provider_url = resp.data.url
  console.log("Successfully started oauth. URL: " + provider_url)
}

Finish OAuth (Exchange Token)

After the user authenticates with the OAuth provider, they will be redirected to the redirect_url you specified. However, to complete the login process with Descope, you'll need to extract the code from the URL and perform the token exchange which will complete the OAuth flow:

// Args:
//   code: code extracted from the url after user is redirected to redirect_url. The code is in the url as a query parameter "code" of the page.
const code = "xxxxx"
 
const response = await descopeClient.oauth.exchange(code);
if (!resp.ok) {
  console.log("Failed to finish oauth")
  console.log("Status Code: " + resp.code)
  console.log("Error Code: " + resp.error.errorCode)
  console.log("Error Description: " + resp.error.errorDescription)
  console.log("Error Message: " + resp.error.errorMessage)
}
else {
  console.log("Successfully finished oauth.")
  console.log(resp)
}

Session Validation

The final step of completing the authentication with Descope is to validate the user session. Descope provides rich session management capabilities, including configurable session timeouts and logout functions. You can find the details and sample code for backend session validation here.

Checkpoint

Your application is now integrated with Descope. Please test with sign-up or sign-in use case.

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Social Login (OAuth) with Backend SDKs