OpenAPI Formatter & Validator
Validate OpenAPI 3 and Swagger 2 documents, then format them as readable JSON or YAML.
Batch workspace
Format multiple files locally in one run.
How to use the OpenAPI Formatter & Validator
Paste code or file
Paste your raw YAML text or upload directly.
Configure options
Choose indentation, dialect, or formatting preferences.
Format & export
Click format, then copy, download, or inspect in tree view.
What is a OpenAPI Formatter & Validator?
Validate OpenAPI 3 and Swagger 2 documents, then format them as readable JSON or YAML. This tool re-indents and organizes code according to standard style conventions while checking for syntax validity. Everything executes 100% inside your browser, guaranteeing zero latency and complete privacy for API keys, user tokens, and confidential database schemas.
Options Explained
| Option | Description |
|---|---|
| Output format | Choose the formatted document output. |
| Result mode | Format the full specification or generate a starter request for its first endpoint. |
| Client language | Language used for the generated starter request. |
| JSON indent | Number of spaces used when JSON output is selected. |
Frequently Asked Questions
Which API specifications are supported?
The tool checks OpenAPI 3.x and Swagger 2.0 documents for required top-level metadata and paths.
Can I convert OpenAPI YAML to JSON?
Yes. Paste YAML or JSON and select JSON output to create a formatted JSON document.
Does this tool send API definitions to a server?
No. Parsing and validation run entirely in your browser.
What does validation check?
It checks the specification version, info.title, info.version, and that at least one API path exists.
Can I format Swagger 2.0 documents?
Yes. Swagger 2.0 documents are accepted alongside OpenAPI 3.x documents.