> 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

# Supported extensions

> See a list of the supported extensions for Docusign extension apps.

The following extensions are available:

| Extension type                                                                               | Extension                                                                                                                      | Extension point                                   | Description                                                                                                         |
| -------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- |
| [Connected fields](/extension-apps/extension-apps-101/supported-extensions/connected-fields) | [Connected fields](/extension-apps/extension-app-reference/extension-contracts/connected-fields)                               | eSignature Add Fields view and Signing            | Perform custom data verification of any types of values against your system of record, and display autofill values. |
| [Data IO](/extension-apps/extension-apps-101/supported-extensions/data-io)                   | [Data IO](/extension-apps/extension-app-reference/extension-contracts/data-io)                                                 | Web Forms, Workflow Builder workflows             | Read data from or write data to your system of record.                                                              |
| Data verification                                                                            | [Bank account owner verification](/extension-apps/extension-app-reference/extension-contracts/bank-account-owner-verification) | eSignature Add Fields view and Signing            | Verify the identity of a bank account owner or authorized signatory.                                                |
| Data verification                                                                            | [Bank account verification](/extension-apps/extension-app-reference/extension-contracts/bank-account-verification)             | eSignature Add Fields view and Signing            | Verify the validity of a signer’s bank account information.                                                         |
| Data verification                                                                            | [Email address verification](/extension-apps/extension-app-reference/extension-contracts/email-address-verification)           | eSignature Add Fields view and Signing, Web Forms | Verify that an email address exists and is deliverable.                                                             |
| Data verification                                                                            | [Business FEIN verification](/extension-apps/extension-app-reference/extension-contracts/business-fein-verification)           | eSignature Add Fields view and Signing            | Verify that a business entity exists and is registered in government databases.                                     |
| Data verification                                                                            | [Phone verification](/extension-apps/extension-app-reference/extension-contracts/phone-verification)                           | eSignature Add Fields view and Signing, Web Forms | Verify that a phone number exists and is reachable.                                                                 |
| Data verification                                                                            | [SSN verification](/extension-apps/extension-app-reference/extension-contracts/ssn-verification)                               | eSignature Add Fields view and Signing            | Verify the validity of an individual's social security number (SSN).                                                |
| Data verification                                                                            | [Postal address verification](/extension-apps/extension-app-reference/extension-contracts/postal-address-verification)         | eSignature Add Fields view and Signing            | Verify the existence and deliverability of a U.S. or international address.                                         |
| File IO                                                                                      | [File input cloud storage](/extension-apps/extension-app-reference/extension-contracts/file-input-cloud-storage)               | Agreement Manager                                 | Import documents from cloud storage.                                                                                |
| File IO                                                                                      | [File input system of record](/extension-apps/extension-app-reference/extension-contracts/file-input-system-of-record)         | Workflow Builder workflows                        | Import documents from a system of record.                                                                           |
| File IO                                                                                      | [File output cloud storage](/extension-apps/extension-app-reference/extension-contracts/file-output-cloud-storage)             | Workflow Builder workflows                        | Write documents to cloud storage.                                                                                   |
| File IO                                                                                      | [File output system of record](/extension-apps/extension-app-reference/extension-contracts/file-output-system-of-record)       | Workflow Builder workflows                        | Write documents to a system of record.                                                                              |
| File IO                                                                                      | [File output tabular format](/extension-apps/extension-app-reference/extension-contracts/file-output-tabular-format)           | Workflow Builder workflows                        | Export data from an agreement to a tabular format file.                                                             |

See [Extensions](/extension-apps/extension-apps-101/concepts/extensions-and-extension-points) and [extension points](/extension-apps/extension-apps-101/concepts/extensions-and-extension-points#extension-points) for details.

> **Note**
>
> Although Docusign continues to support existing extension apps that use the file archive extension, new extension apps should use the [file output cloud storage extension](/extension-apps/extension-apps-101/supported-extensions/file-output-cloud-storage) instead.

## Next steps

* Learn about [Extension app use cases](/extension-apps/extension-apps-101/use-cases).
* See details for an [Example extension app use cases](/extension-apps/build-an-extension-app/example-use-case).
* View the [App manifest reference](/extension-apps/extension-app-reference/app-manifest-reference) for a full list of supported elements.
* Get an introduction to [Extension app concepts](/extension-apps/extension-apps-101/concepts).