# Insomnia Collection
source: https://developer.mastercard.com/merchant-identifier/documentation/developer-tools/insomnia-collection/index.md

## Insomnia Collection {#insomnia-collection}

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

For the full step-by-step guide, see the [Insomnia tutorial](https://developer.mastercard.com/platform/tutorial/use-insomnia-rest-client-for-mastercard-apis/).

## Overview {#overview}

The Insomnia guide covers how to set up Mastercard API requests in Insomnia, including plugin installation, workspace import options, environment configuration, and request execution.

## Prerequisites {#prerequisites}

* You have access to a Mastercard Developers project with the credentials required by the API testing
* You have installed Insomnia on your machine
* You have the required authentication and encryption details for the service you want to call

## What You Will Find {#what-you-will-find}

* Plugin installation options for Insomnia
* Import guidance for collections and workspace templates
* Environment setup for OAuth 1.0a, OAuth 2.0, and JWE-enabled flows
* Practical steps for sending and validating requests in Sandbox and Production