I want to create a mock server for front end developers of our team.

Here is my sample api-y.yaml file:

openapi: 3.0.0
info:
  title: Mock API
  description: A simple mock API
  version: 1.0.0
paths:
  /api/hello:
    get:
      summary: Returns a hello message
      responses:
        '200':
          description: A hello message
          content:
            application/json:
              schema:
                type: object
                properties:
                  message:
                    type: string
                    example: Hello, world!

program.cs:

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();
builder.Services.AddSwaggerGen();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseAuthorization();
app.MapControllers();

app.Run();

What else should I do in order to see /api/hello endpoint in Swagger when I run my project?

I tried sample code I found online and I got from ChatGPT but I wasn’t successful

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllers();

builder.Services.AddSwaggerGen(options =>
{
    options.IncludeXmlComments(Path.Combine(AppContext.BaseDirectory, "api-j.yaml"));
});

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

app.UseAuthorization();
app.MapControllers();
app.Run();

I also tried using JSON file:

{
  "openapi": "3.0.0",
  "info": {
    "title": "Mock API",
    "description": "A simple mock API",
    "version": "1.0.0"
  },
  "paths": {
    "/api/hello": {
      "get": {
        "summary": "Returns a hello message",
        "responses": {
          "200": {
            "description": "A hello message",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "message": {
                      "type": "string",
                      "example": "Hello, world!"
                    }
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}