How to convert OpenAPI 2.0 to OpenAPI 3.0? [closed]

Answer 1

Swagger Editor

Paste your OpenAPI 2.0 definition into https://editor.swagger.io and select Edit > Convert to OpenAPI 3 from the menu.

Swagger Converter

Converts OpenAPI 2.0 and Swagger 1.x definitions to OpenAPI 3.0.

https://converter.swagger.io/api/convert?url=OAS2_YAML_OR_JSON_URL

This gives you JSON. If you want YAML, send the request with the Accept: application/yaml header:

curl "https://converter.swagger.io/api/convert?url=OAS2_YAML_OR_JSON_URL" -H "Accept: application/yaml" -o ./openapi.yaml

API docs: https://converter.swagger.io

GitHub repo: https://github.com/swagger-api/swagger-converter

Swagger Codegen version 3.x

Can also convert OpenAPI 2.0 and Swagger 1.x definitions to OpenAPI 3.0. Swagger Codegen has a CLI version, Maven plugin, Docker images.

Here's an example using the command-line version (you can download the latest JAR from Maven Central). Write the entire command on one line. Use openapi-yaml to get YAML or openapi to get JSON.

java -jar swagger-codegen-cli-3.0.19.jar generate
     -l openapi-yaml
     -i https://petstore.swagger.io/v2/swagger.yaml
     -o OUT_DIR

GitHub repo: https://github.com/swagger-api/swagger-codegen