Mock sample for your project: Medium.com - Unofficial API Spec

The Org Policy API allows users to configure governance rules on their GCP resources across the Cloud Resource Hierarchy.

Giphy API

Views Ad Experience Report data, and gets a list of sites that have a significant number of annoying ads.

Searches the Google Knowledge Graph for entities.

Manipulates events and other calendar data.

The Flat API allows you to easily extend the abilities of the Flat Platform, with a wide range of use cases including the following:
Creating and importing new music scores using MusicXML, MIDI, Guitar Pro (GP3, GP4, GP5, GPX, GP), PowerTab, TuxGuitar and MuseScore files
Browsing, updating, copying, exporting the user's scores (for example in MP3, WAV or MIDI)
Managing educational resources with Flat for Education: creating & updating the organization accounts, the classes, rosters and assignments.
The Flat API is built on HTTP. Our API is RESTful It has predictable resource URLs. It returns HTTP response codes to indicate errors. It also accepts and returns JSON in the HTTP body.
The schema of this API follows the OpenAPI Initiative (OAI) specification, you can use and work with compatible Swagger tools.
This API features Cross-Origin Resource Sharing (CORS) implemented in compliance with W3C spec.
You can use your favorite HTTP/REST library for your programming language to use Flat's API. This specification and reference is available on Github.
Getting Started and learn more:
API Overview and introduction
Authentication (Personal Access Tokens or OAuth2)
SDKs
Rate Limits
Changelog

Reads and writes Google Forms and responses.

Writes log entries and manages your Cloud Logging configuration.

Description of Instagram RESTful API.
Current limitations:
Instagram service does not support cross origin headers
for security reasons, therefore it is not possible to use Swagger UI and make API calls directly from browser.
Modification API requests (POST, DELETE) require additional security scopes
that are available for Apps created on or after Nov 17, 2015 and
started in Sandbox Mode.
Consider the Instagram limitations for API calls that depends on App Mode.
Warning: For Apps created on or after Nov 17, 2015 API responses
containing media objects no longer return the data field in comments and likes nodes.
Last update: 2015-11-28

Creates and manages builds on Google Cloud Platform.

The Google Cloud Deployment Manager v2 API provides services for configuring, deploying, and viewing Google Cloud services and APIs via templates which specify deployments of Cloud resources.