Swagger 2.0 to OpenAPI 3 Converter

How to use this developer tool

1. Paste a JSON-formatted API document or load the included sample.
2. Check that the document shape matches the label above the editor.
3. Select “Convert to OpenAPI 3” or press Ctrl/Cmd + Enter.
4. Review the summary and download the copy-ready result.

What this developer tool does

The converter performs a practical structural migration while preserving paths, operations, descriptions, extensions, and reusable component names.

The result targets OpenAPI 3.0.3 and should be reviewed where Swagger collection formats or file uploads were used.

Example

The Sample button loads a small specification chosen for this operation. Running it produces the same structured fields shown in the output panel.

{
  "swagger": "2.0",
  "info": {
    "title": "Pet API",
    "version": "1"
  },
  "basePath": "/v1",
  "schemes": [
    "https"
  ],
  "host": "api.example.com",
  "consumes": [
    "application/json"
  ],
  "produces": [
    "application/json"
  ],
  "definitions": {
    "Pet": {
      "type": "object",
      "properties": {
        "name": {
          "type": "string"
        }
      }
    }
  },
  "paths": {
    "/pets": {
      "post": {
        "parameters": [
          {
            "name": "body",
            "in": "body",
            "required": true,
            "schema": {
              "$ref": "#/definitions/Pet"
            }
          }
        ],
        "responses": {
      
…

Use cases

• Review an API contract during a pull request.
• Prepare documentation or deterministic test fixtures.
• Find migration work before changing generators or clients.
• Export a focused report without sharing the source document.

Tips for reliable output

• Bundle remote references before running the page.
• Keep operation IDs stable across published versions.
• Prefer explicit examples for domain-specific values.
• Validate the complete document after applying generated output.
• Commit the original specification before a conversion.

Processing details

The source is deep-cloned, Swagger-only root fields are removed, local reference prefixes are rewritten, and operation request/response payloads are migrated.

Complex formData encoding, OAuth flow translation nuances, file uploads, callbacks, and vendor-specific behavior may require manual adjustments.