> 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 contracts

> Reference for Docusign extension contracts.

Each extension has an extension contract: a set of [actions](/extension-apps/extension-apps-101/concepts/actions) and [capabilities](/extension-apps/extension-apps-101/concepts/capabilities) that are supported for the extension.

See the contract details for each extension:

#### Connected fields

* [Connected fields](/extension-apps/extension-app-reference/extension-contracts/connected-fields)

#### Data IO

* [Data IO](/extension-apps/extension-app-reference/extension-contracts/data-io)

#### Data verification

* [Bank account owner verification](/extension-apps/extension-app-reference/extension-contracts/bank-account-owner-verification)
* [Bank account verification](/extension-apps/extension-app-reference/extension-contracts/bank-account-verification)
* [Business FEIN verification](/extension-apps/extension-app-reference/extension-contracts/business-fein-verification)
* [Email address verification](/extension-apps/extension-app-reference/extension-contracts/email-address-verification)
* [Phone verification](/extension-apps/extension-app-reference/extension-contracts/phone-verification)
* [Postal address verification](/extension-apps/extension-app-reference/extension-contracts/postal-address-verification)
* [SSN verification](/extension-apps/extension-app-reference/extension-contracts/ssn-verification)

#### File IO

* [File input cloud storage](/extension-apps/extension-app-reference/extension-contracts/file-input-cloud-storage)
* [File input system of record](/extension-apps/extension-app-reference/extension-contracts/file-input-system-of-record)
* [File output cloud storage](/extension-apps/extension-app-reference/extension-contracts/file-output-cloud-storage)
* [File output system of record](/extension-apps/extension-app-reference/extension-contracts/file-output-system-of-record)
* [File output tabular format](/extension-apps/extension-app-reference/extension-contracts/file-output-tabular-format)

To suggest an extension, please visit the [Docusign Developer Community](https://community.docusign.com/developer-59).

## Next steps

* Learn more about

  [extensions and extension points](/extension-apps/extension-apps-101/concepts/extensions-and-extension-points)

  .
* Learn

  [how extensions relate to other manifest components](/extension-apps/extension-apps-101/inside-an-extension-app)

  .