Elastic uses the OpenAPI specification, previously known as Swagger, to document its Elastic Cloud Enterprise (ECE) REST API, which facilitates cluster management and automation tasks. The OpenAPI specification serves as a language-agnostic interface, enabling both humans and computers to understand the API's capabilities without requiring source code access. This specification aids in generating REST clients in various languages, which is beneficial for creating custom software layers around ECE. The blog post details how to retrieve the OpenAPI specification through an API or documentation, and explains how to use tools like Swagger Editor and Swagger Codegen to generate clients in languages such as Java and Python. The process involves obtaining Swagger Codegen, running it with specific commands to generate client code, and using the resulting client to perform tasks like retrieving and creating Elasticsearch clusters. Despite some known issues with Swagger Codegen in certain languages, the specification's flexibility allows for alternative community generators or even custom development.