Single Sign On (SSO) with Backend SDKs

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

If you'd like to use Descope Flows, Quick Start should be your starting point.

Descope supports SSO as one of the authentication methods for your end-users. When using SSO, the SSO configuration can be different for each tenant. Descope supports OIDC and SAML identity providers, specific to each Tenant. Please refer to the article in the manage section for the configuration of SAML or OIDC for each tenant.

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)
}
 
// Note that you can handle async operation failures and capture specific errors to customize errors.
//     An example can be found here: https://github.com/descope/node-sdk?tab=readme-ov-file#error-handling

Start SSO

The first step is to start the SSO authentication process with the Identity Provider. For this step you need call sso start function from your app client after user clicks on login icon.

// Args:
//   tenant_id: ID of the tenant that the user is authenticating to. The tenant ID is assigned to tenant at the time of creation.
const tenant_name_id_or_email = "xxxx"
//   redirect_url: URL to return to after successful authentication with the SSO 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.saml.start(tenant_name_id_or_email, redirect_url, loginOptions);
if (!resp.ok) {
  console.log("Failed to start sso auth")
  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 url = resp.data.url
  console.log("Successfully started sso auth. URL: " + url)
}

SSO Exchange Code

After successful authentication with your IdP the user is redirected to the redirect_url that you provide in the sso start function above. Your application should extract the code from the redirect_url and perform token exchange as shown below.

// 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 resp = await descopeClient.saml.exchange(code);
if (!resp.ok) {
  console.log("Failed to verify sso code")
  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 verified sso code.")
}

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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