OpenAPI YAML to JSON Converter

Convert OpenAPI/Swagger YAML to JSON entirely in your browser. Fast, free, and private.

Input YAML
Output JSON

All conversions happen locally in your browser. No files are uploaded and no network requests are made. Code is open source.

About OpenAPI YAML to JSON Converter

A fast, free, browser-based OpenAPI YAML to JSON converter for API specifications. Convert OpenAPI and Swagger definitions between YAML and JSON with zero setup. The tool works seamlessly with OpenAPI 3.0, OpenAPI 3.1, and Swagger 2.0 (OpenAPI 2.0).

Key Features

  • Instant conversion: Transform Swagger/OpenAPI YAML ↔ JSON in real time
  • Flexible input: Paste content, upload files, or fetch from a URL
  • Standards support: Compatible with OpenAPI 3.0, 3.1, and Swagger 2.0
  • Smart detection: Automatically identifies YAML or JSON input
  • Private by design: All processing runs locally in your browser
  • Export ready: Copy to clipboard or download the converted spec

How to Convert OpenAPI YAML to JSON

  1. Add your spec: Paste YAML, upload a .yaml file, or provide a URL
  2. View the result: Conversion to JSON happens instantly
  3. Save or share: Copy the output or download the JSON file

Supported Formats

The converter supports the most widely used API specification formats:

  • OpenAPI 3.1 — Modern OAS with full JSON Schema alignment
  • OpenAPI 3.0 — The widely adopted successor to Swagger 2.0
  • Swagger 2.0 — Legacy (OpenAPI 2.0) specifications

Why Convert Between YAML and JSON?

YAML is concise and human-readable, ideal for authoring and reviewing API definitions. JSON is compact and broadly supported across tooling, CI/CD, and SDK generators. Teams often convert to:

  • Integrate with documentation, testing, and gateway platforms
  • Collaborate across teams with different format preferences
  • Reduce file size for builds and deployments
  • Meet pipeline or validator requirements for a specific format

Common Use Cases

API Documentation

Convert your OpenAPI files to the format required by tools such as Swagger UI, Redoc, or Postman.

API Gateway Configuration

Match the input format expected by popular API gateways by converting between YAML and JSON.

Version Control

Prefer YAML for clearer diffs in Git, or convert to JSON for tooling that requires it.

API Testing

Provide your test frameworks and validators with specs in their preferred format.

Frequently Asked Questions

Is this OpenAPI converter free to use?

Yes. The converter is completely free—no registration or payment needed.

Does the converter support Swagger 2.0?

Yes. It supports Swagger 2.0 (OpenAPI 2.0) as well as OpenAPI 3.0 and 3.1.

Is my API specification data secure?

Absolutely. Conversion runs locally in your browser—your files are not uploaded to a server.

Can I convert large OpenAPI files?

Yes. The in-browser approach handles large specifications efficiently, without external upload limits.

What's the difference between OpenAPI and Swagger?

Swagger was renamed to the OpenAPI Specification in 2016; “Swagger” commonly refers to the tooling ecosystem, while “OpenAPI” refers to the specification itself.

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