--- title: "Migrate from connected app to external client app" slug: "migrate-from-connected-app-to-external-client-app" description: "Migrate from connected apps to external client apps in Salesforce for API integrations. Follow our guide for a seamless transition and troubleshooting tips." updated: 2026-08-13T21:10:03Z published: 2026-08-13T21:10:03Z canonical: "support.fullcast.com/migrate-from-connected-app-to-external-client-app" stale: true --- > ## Documentation Index > Fetch the complete documentation index at: https://support.fullcast.com/llms.txt > Use this file to discover all available pages before exploring further. # Migrate from connected app to external client app Salesforce has replaced connected apps with external client apps as the supported authentication model for API integrations. See [Create an external client app](https://support.fullcast.com/docs/en/connect-an-external-client-app) for why migration matters and when it becomes required. Use this article to migrate an existing connection from a connected app to an external client app. > [!NOTE] > **Note** > > Once you disconnect the legacy connected app, you cannot fall back to it. All new or re-established connections must use the external client app. ## Before you begin - Check your current connection type in Fullcast: Navigate to **Settings > Export-Import**. If under **Connections > Type** it shows as **Salesforce**, you cannot migrate it yourself — file a request with Fullcast support to convert it to the current connection type, then continue with this article. ![Settings page showing Export-Import options and Salesforce connection details.](https://cdn.document360.io/369efcf7-66f9-4f6b-9d45-9ca24a5b06cf/Images/Documentation/image-1786655163444.png) - Confirm the Fullcast [integration user exists and has the correct permission sets](/plan-and-pay/docs/create-an-integration-user). - Confirm your Salesforce org allows the integration user to complete an interactive OAuth handshake. If your org enforces SSO, the integration user must either: Contact your Salesforce administrator if you are unsure. - Be provisioned in your Identity Provider (Okta, Azure AD, or equivalent), or - Be assigned to a Salesforce profile where **Is Single Sign-On Enabled** is unchecked. - Check the **Disable login with Salesforce credentials** setting in your Salesforce org under **Setup > Single Sign-On Settings**. If this setting is enabled and your integration user is not provisioned in your Identity Provider, the OAuth handshake will fail during the external client app connection step. - Schedule a maintenance window. Data syncs will pause between disconnecting the connected app and completing the external client app setup. ## Create the external client app in Salesforce Create a new external client app in Salesforce for Fullcast. This app replaces the legacy connected app and provides the consumer key and consumer secret you will use in the next section. 1. Follow the steps in [Create an external client app](https://support.fullcast.com/docs/en/connect-an-external-client-app) to complete the OAuth settings and policies in Salesforce. > [!NOTE] > **Note** > > Keep the **Consumer Key** and **Consumer Secret** available. You will paste them into Fullcast in the next section. ## Connect Fullcast to the new external client app After the external client app is created in Salesforce, disconnect the legacy connected app in Fullcast and authenticate the new external client app. For the full step-by-step authorization flow, see [Connect Fullcast to Salesforce with external client app](https://support.fullcast.com/docs/en/connect-fullcast-to-salesforce-with-external-client-app). ## Verify the migration Confirm the new external client app connection is working before you remove the legacy connected app. 1. In Fullcast, go to **Settings > Export-Import** and confirm the connection status shows as connected. 2. Run a small test import job and confirm the job completes successfully. 3. Confirm data is flowing between Salesforce and Fullcast as expected. 4. In Salesforce, go to **Setup > Users > Login History** and confirm the integration user's most recent logins are authenticated through the external client app. ## Optional. Remove the legacy connected app Once the external client app is confirmed working and data syncs have resumed successfully, you can remove the legacy connected app from Salesforce. 1. In Salesforce, go to **Setup > Apps > App Manager**. 2. Locate the Fullcast connected app in the list. 3. From the row's action menu, select **Delete** and confirm. ## Troubleshooting If the browser authorization fails with a redirect loop or a 500 error, the most likely cause is an SSO policy blocking the integration user. Verify the SSO checklist in the [Before you begin](/plan-and-pay/docs/migrate-from-connected-app-to-external-client-app#before-you-begin) section. If the issue persists, contact your CSM. **Customer success manager:** A customer service support person who ensures customers achieve their desired outcomes and receive maximum value from Fullcast. ## Related - [Create an external client app](/connect-an-external-client-app.md) - [Connect Fullcast to Salesforce with external client app](/connect-fullcast-to-salesforce-with-external-client-app.md)