How to validate API-Document (swagger.json)'s compatibility with OpenAPI Spec?

[KuldeepSinh]

Many a times our API Specification docs (swagger.json) are malformed and that being the reason our generated C# Client code does not compile.

To catch such issues before the code generation, we need to validate our API Specification (swagger.json)'s correctness and compatibility with the OpenAPI 3.1 specification.

I am not aware if NSwag's C# Client Generator has a way to validate swagger.json out of the box. I tried achieving same using NJsonSchema library.

I am getting following error, when it tries to read openApiSpecification (at line : var schema = await JsonSchema.FromJsonAsync(schemaData);)

Unhandled exception. Newtonsoft.Json.JsonSerializationException: Unexpected initial token 'Boolean' when populating object. Expected JSON object or array. Path 'patternProperties.^x-', line 1, position 107.
...

My code looks like this.

using NJsonSchema;
using NJsonSchema.Validation;

namespace SwaggerValidator
{
    public class Program
    {
        public static async Task Main(string[] args)
        {
            var swaggerData = File.ReadAllText("swagger.json");
            var schemaData = File.ReadAllText("OpenApiSchema.json");
            var schema = await JsonSchema.FromJsonAsync(schemaData);
            var validator = new JsonSchemaValidator();
            var result = validator.Validate(swaggerData, schema);
        }
    }
}

Is there any example/code I can refer to? I admit that JSonSchema != OpenApiSchema and I was not able to figure out appropriate solution.

Thank you.