OpenAPI Tester Converter
Convert an OpenAPI 3 JSON or YAML file into a more permissive tester OpenAPI spec for exploratory API testing.
Load an OpenAPI JSON or YAML file, then choose a tester profile.
Convert OpenAPI To A More Permissive Tester Spec
Strict OpenAPI files are useful documentation, but they can also limit testing. A schema might require a field, restrict a value to an enum, hide an unsupported HTTP method, or stop Swagger UI and REST clients from making the unusual request you want to investigate.
This browser tool converts an OpenAPI 3 file into a less restrictive tester OpenAPI spec. The conversion happens in your browser. Local files are not uploaded to API Challenges.
The output is useful for exploratory API testing, negative testing, contract comparison, and importing a more flexible API description into tools that can read OpenAPI files.
Create Practical Or Aggressive OpenAPI Testing Files
The Practical profile removes common schema validation restrictions and adds the common REST methods: GET, POST, PUT, PATCH, DELETE, OPTIONS, and HEAD. Use it when you want a less restrictive file that still feels close to a normal REST API contract.
The Aggressive profile applies the same relaxation and adds every selectable OpenAPI method to every path, including TRACE. It also adds loose JSON request bodies to generated body-capable operations. Use it when you want to push an API harder and see how the real server behaves outside the documented happy path.
Choose Custom when you want to decide exactly which validation rules to remove and which HTTP methods to add.
Download A Less Restrictive OpenAPI File For REST Client Testing
After conversion, copy the JSON or download the tester OpenAPI file. You can import the converted file into REST clients that support OpenAPI, or use it as a reference while sending requests with the Basic Client.
For more tool options, compare the REST/HTTP client summary reviews, read the REST/HTTP Clients overview, or review detailed notes for Bruno, Postman, Insomnia, and cURL.
Use Converted OpenAPI Files In Swagger UI And REST Clients
Use the Open in Swagger UI button to render the converted tester spec in the Online Swagger UI. Swagger UI will show the generated operations and the relaxed request shapes so you can try requests from the browser.
If this is your first time using OpenAPI or REST clients, follow How to Test REST APIs, the API Simulator Walkthrough, the Swagger UI and Tools guide, or the OpenAPI for API Testing reference first.
For examples of standard and less-validating OpenAPI files generated by this site, compare the API Challenges OpenAPI Files, Simple API OpenAPI Files, and Buggy API OpenAPI Files.
CORS Limits For Browser OpenAPI Conversion
Because this converter runs in the browser, URL loading is limited by CORS.
CORS means Cross-Origin Resource Sharing. It is the browser rule that controls whether JavaScript from one origin can call another origin. If the OpenAPI URL does not allow this site, the browser may block loading the file. Download the file and open it from disk if the server does not allow browser access.
The converted file can describe methods such as TRACE, but browsers may still block some methods or requests when you try them from Swagger UI. Use a desktop REST client, command line client, or HTTP proxy when you need to avoid browser limits or inspect raw traffic.