# Functions Reference – DigitalOcean Documentation

> CLI documentation for functions, including example requests and available parameters, and other reference information like project YAML configuration and activation records.
- [Activation Record JSON Structure](https://docs.digitalocean.com/products/functions/reference/activation-records/index.html.md): Each asynchronous activation of a function creates an activation record, which you can retrieve to learn more about the process. Activation records are a JSON object, the structure of which is documented here.
- [HTTP Headers](https://docs.digitalocean.com/products/functions/reference/http-headers/index.html.md): HTTP headers used by Functions.
- [Parameters and Responses](https://docs.digitalocean.com/products/functions/reference/parameters-responses/index.html.md): Functions receive two parameters, event and context, and should return a single value.
- [Project Configuration YAML File](https://docs.digitalocean.com/products/functions/reference/project-configuration/index.html.md): The project.yml file is a YAML configuration file in the root directory of a project which lets you define environment variables, parameters, and other properties for the project and the packages and functions within it. The structure of the information in …
- [Build Process](https://docs.digitalocean.com/products/functions/reference/build-process/index.html.md): The Functions service performs a build process to transform your project’s source code into executable functions. Though much of the build runs in your own build scripts, there are other details about the Functions build process that are useful to …



## Supported Runtimes for DigitalOcean Functions

Reference information for supported Functions runtimes.

- [Functions Go Runtime](https://docs.digitalocean.com/products/functions/reference/runtimes/go/index.html.md): Details on developing Functions using Go.
- [Functions Node.js JavaScript Runtime](https://docs.digitalocean.com/products/functions/reference/runtimes/node-js/index.html.md): Details on developing Functions using Node.js JavaScript.
- [Functions PHP Runtime](https://docs.digitalocean.com/products/functions/reference/runtimes/php/index.html.md): Details on developing Functions using PHP.
- [Functions Python Runtime](https://docs.digitalocean.com/products/functions/reference/runtimes/python/index.html.md): Details on developing Functions using Python.