> You are reading the Docusign Developer Documentation. For clean Markdown of any page, append .md to the page URL.
>
> Documentation indexes by section:
> - APIs and SDKs: https://docusign.docs.buildwithfern.com/docs/llms.txt
> - Platform 101: https://docusign.docs.buildwithfern.com/platform/llms.txt
> - Extension Apps: https://docusign.docs.buildwithfern.com/extension-apps/llms.txt
> - Docusign CLI: https://docusign.docs.buildwithfern.com/docusign-cli/llms.txt
>
> Authentication (OAuth, JWT Grant, M2M): https://docusign.docs.buildwithfern.com/platform/auth
> Webhooks and Connect: https://docusign.docs.buildwithfern.com/platform/webhooks
>
> OpenAPI specifications: https://docusign.docs.buildwithfern.com/openapi.json
> MCP server: https://docusign.docs.buildwithfern.com/_mcp/server

# Extension app use cases

> See how extension apps can help you simplify document preparation, signing, and post-signing tasks.

You can use extension apps to simplify tasks during document preparation, signing, and post-signing. Some examples of extension app use cases include:

* Verifying bank account information in a financial agreement
* Address verification
* Recording data to your system of record
* Reading data from your proprietary system

![Image showing an example flow where an extension app is used to verify data](/_fern-files/_img/29474663dea190dba5455dc82a596256c84333c1154726c9f368933113626d06.webp)

## Example data verification use case

1. A developer [builds](/extension-apps/build-an-extension-app) a data verification extension app.
2. The developer submits their extension app for review with Docusign.
3. The developer [publishes](/extension-apps/build-an-extension-app/publish) their extension app to the Docusign App Center, either as a **public** or [private](/extension-apps/extension-apps-101/choosing-private-distribution) extension app.
4. If it was built as a public extension app, a customer admin, looking for an app that can improve their organization’s processes, **finds the app and installs it**. If the app is private, only the owners of the accounts selected by the extension app developer can find and install it.
5. The extension app’s [Connection](/extension-apps/extension-apps-101/concepts/connections) is configured to connect to the external platform that performs the data verification (for example, a bank account or email address verification service).
6. A customer process builder uses the [Workflow Builder API](/docs/workflow-builder-api) or [Workflow Designer](https://apps-d.docusign.com/send/workflows/) to **create a workflow**. This workflow includes:

   1. A document that includes data verification fields that are connected to a data verification extension app
   2. An envelope signing step
7. Whenever that customer’s users sign that envelope as part of the Workflow Builder workflow, the **extension app will be executed** during the signing process. The extension app will validate the user’s entered information, such as a bank account number or email address, through the external platform. If the verification is successful, the signing continues. If not, the user is prompted to update the information.

![Image showing an example data verification extension being created, published, and used.](/_fern-files/_img/2aac97f208c0a3fcb06587d3a082f0e39f7edddd59dc279e47744aaae39c0bde.webp)

## Next steps

* Learn more about [How extension apps work](/extension-apps/extension-apps-101/how-extension-apps-work).
* See an [Example extension app use cases](/extension-apps/build-an-extension-app/example-use-case).
* Learn more about how to [Build an extension app](/extension-apps/build-an-extension-app).