## Authentication

- [### Authenticate to Application Integration
  This document describes how to authenticate to Application Integration if you
  are using REST.](https://docs.cloud.google.com/application-integration/docs/authentication)

## Application Integration API

- [### V1 API reference
  Programming reference for the V1 Application Integration API.](https://docs.cloud.google.com/application-integration/docs/reference/rest)
- [### V2 API reference
  Programming reference for the V2 Application Integration API.](https://docs.cloud.google.com/application-integration/docs/reference/rest)