Criteria Playground

Visualize, edit & test REST APIs online. Criteria Playground is a completely free and easy way to get started with the OpenAPI Specification (formerly known as Swagger).

  • Generate developer-friendly documentation

  • Get feedback by sharing permalinks

  • Test endpoints in an interactive API Explorer

  • Enforce style guides with Spectral rulesets

  • Runs anywhere on the web

  • Works with your local files

  • Supports OpenAPI v3.0 and v3.1 and JSON Schema

Go to Criteria Playground

Completely free, no account required.

Screenshot of Criteria Playground editor

Explore these popular APIs

View API documentation for popular services and try them out in a free, online interactive API Explorer.

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    A REST API interface for integrating OpenAI's machine-learning models into applications.
  • Plaid Logo


    Integrate with the Plaid REST API.
  • PayPal Logo


    Explore the specification files for the PayPal REST APIs.

Powerful OpenAPI editor

Criteria Playground provides a full IDE experience for editing REST APIs, with support for OpenAPI 3.0 and 3.1, and the JSON Schema specification.

  • Use your Local Files

    Criteria Playground works as an IDE, using the files and folders on your computer. No data hostage.

  • Real-Time Linting

    Lint your APIs and get immediate feedback with built-in support for Spectral rulesets. No installation required.

  • Multi-File Support

    Reuse components and schemas with full support for $ref and $dynamicRef keywords.

  • Template Library

    Get started quicker with templates for OpenAPI and JSON Schema files.

Screenshot of Criteria Playground API Issues view
Criteria Playground API Issues view showing a highlighted issue generated by a Spectral Ruleset and its location in code in the editor.

Collaborative API design

Criteria Playground is designed to be collaborative experience so you can get fast feedback on your API. Share your API with product managers, customers and other stakeholders quickly and easily.

Screenshot of Criteria Playground API documentation
Criteria Playground API documentation showing the generated documentation for a request with request body schema, example cURL code and response body JSON data.
  • Generate API documentation

    Create modern, beautiful documentation from your OpenAPI definition instantly.

  • Link sharing

    Share your API as a permalink with unlimited viewers. No need to set up additonal logins or pay for extra seats.

  • Generated Code Samples

    Copy sample JSON and cURL code snippets.

Online API testing

Criteria Playground comes with a free, online API client, so you can test any REST API using nothing more than its OpenAPI document.

  • Interactive API Explorer

    Make API requests and inspect responses directly in the browser.

  • Easy-to-use API client

    HTTP requests are autogenerated from your OpenAPI file. No more 400 errors.

  • Authentication

    Test secure APIs with support for HTTP Basic Auth, API keys, bearer tokens and OAuth 2.0 flows.

Screenshot of Criteria API Explorer
Criteria Playground API Explorer showing the response body of a previous request that was sent from the browser.

Frequently asked questions

How much does Criteria Playground cost?
Criteria Playground is a free to use.
Which specification formats are supported?
The OpenAPI Specification versions 3.0 and 3.1 are supported. The JSON Schema Specification is supported for drafts 04, 06, 07 and 2020-12.
Where are my files stored?
Criteria Playground stores files locally in the Origin Private File System. You can also open and save files and folders on your computer to use Criteria Playground as an IDE for your source code.
What browsers are supported?
Criteria Playground uses the File System API web standard, which is supported across all major browsers. Though some browsers have more complete implementations than others. As of April 2024, Chrome or Edge have the most complete support. Please report any browser compatibility issues to
Is Criteria Playground open source?
The web application is not open source.
Can I share API links privately?
Private sharing is a paid feature. Please contact to set up private sharing.
Can I publish API documentation on a custom domain?
Documentation hosting is a paid feature. Please contact to set up a custom domain.

Accelerate your API delivery

Import your OpenAPI document to start designing, documenting and testing your API in an integrated experience.

Import your OpenAPI file

Completely free, no account required.