> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://mailchimp.com/developer/marketing/api-concepts/api-structure/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://mailchimp.com/_mcp/server. # API structure > How the Marketing API is organized—REST conventions and the root URL. The Marketing API generally follows REST conventions, with some deviations. * *Resources* are typically nouns like `subscribers` or `campaigns`. * *Subresources* can be multiply nested under resources. * *Actions* are usually represented by [HTTP methods](/marketing/api-concepts/methods-and-parameters). Actions that do not correspond to HTTP methods are collected under an `actions/` subresource. * *Responses* use the generic JSON content type. We use the [OpenAPI Specification](https://www.openapis.org/) (formerly known as Swagger) to describe each endpoint. [The API self-description](https://api.mailchimp.com/schema/openapi/OpenAPI.json?expand) also contains type information to help you error-check your requests. The root url for the API is `https://api.mailchimp.com/3.0/`. All API endpoints for your account are available relative to this URL. For more details on how to query Marketing API endpoints, see [Methods and Parameters](/marketing/api-concepts/methods-and-parameters). For troubleshooting API calls, see the [Errors](/marketing/api-concepts/errors) docs. > Find all the Mailchimp API documentation and tools developers need to send marketing and transactional emails.