Stoplight Scenarios is a powerful (but accessible!) tool that takes the pain out of API testing. It is a standalone product, available on [the web](https://scenarios.stoplight.io), and as a [desktop app](https://download-next.stoplight.io).

We generally recommend the desktop app when possible. It works with local servers, behind firewalls, and exchanges information with tools on your computer like Git or your favorite IDE. You can switch seamlessly between the desktop app and the web app.

We engineered Scenarios from the ground up to be:

- **Powerful** Easily assert, capture, transform, and validate your API Spec (Swagger) against your actual API. And if that isn’t enough, Prism has a powerful javascript runtime.

- **Portable** Scenarios are described in plain JSON with a well thought out, robust specification. Use our visual editor to quickly generate and manage this JSON. They can be run from our visual tooling, or completely outside of Stoplight, on your own machines or on your continuous integration server.

- **Flexible** Your APIs, your tests, your way. Scenarios only test what you want them to. They have no opinion about your architecture (Monolithic vs Microservices), company structure (in house vs distributed), development lifecycle (production vs TDD), and your environment (development vs staging vs production).

- **Fast** Time can’t be slowed down, and we can’t give it back to you. Creating tests should be quick, and waiting for you tests to run shouldn’t feel like watching water boil. Scenarios are run concurrently for maximum speed - run hundreds of API requests and test assertions in seconds.

### Editor UI Overview

![](https://cdn.stoplight.io/help-portal/scenarios/scenario-editor-callout.png)
