# Insomnia Collection
source: https://developer.mastercard.com/mastercom-extended/documentation/developer-tools/insomnia/index.md

## Overview {#overview}

Use Insomnia to test Mastercard APIs with a ready-made workflow for importing requests, configuring environments, and validating calls in Sandbox or Production.

[Insomnia](https://insomnia.rest/) is an open-source API client that developers use to quickly and easily send REST requests to Mastercard APIs. API Consultancy \& Standards developed an [Insomnia Plugin](https://github.com/Mastercard/insomnia-plugin-mastercard) for handling API authentication.

## Prerequisites {#prerequisites}

1. [Insomnia](https://insomnia.rest/) installed.
2. Mastercard Developer project with sandbox and production credentials.
3. Correct authentication and encryption details.

## Tutorial {#tutorial}

Follow our [Insomnia Tutorial](https://developer.mastercard.com/platform/tutorial/use-insomnia-rest-client-for-mastercard-apis/) to learn how to test the OAuth API using Insomnia.

Estimated completion time: 10 minutes