/ Existing Blazor project: Program.cs (Startup class)
public void ConfigureServices(IServiceCollection services)
{
    // ... other service registrations

    services.AddEndpointsApiExplorer();

    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "My Blazor API", Version = "v1" });
    });
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    // ... other configuration

    app.UseSwagger();

    app.UseSwaggerUI(c =>
    {
        c.SwaggerEndpoint("/swagger/v1/swagger.json", "My Blazor API v1");
    });

    app.MapGet("/api/weather", async (httpContext) =>
    {
        // Fetch weather data from your service
        var forecasts = await _weatherService.GetForecasts();
        await httpContext.Response.WriteAsJsonAsync(forecasts);
    });