Scalar

using Scalar.AspNetCore;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddOpenApi();

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
    app.MapScalarApiReference();  // UI at /scalar/v1
}

app.Run();

app.MapScalarApiReference(options =>
{
    options
        .WithTitle("Checkout API")
        .WithTheme(ScalarTheme.Mars)
        .WithDefaultHttpClient(ScalarTarget.CSharp, ScalarClient.HttpClient)
        .WithPreferredScheme("Bearer")
        .WithProxy(null)  // Disable external proxy
        .WithSidebar(true);
});

if (app.Environment.IsDevelopment())
{
    app.MapScalarApiReference(options =>
    {
        options
            .WithPreferredScheme("Bearer")
            .AddHttpAuthentication("Bearer", auth =>
            {
                auth.Token = "dev-only-test-token";
            });
    });
}

// API Key
options.WithApiKeyAuthentication(apiKey =>
{
    apiKey.Token = "dev-api-key";
});

// OAuth2
options.WithOAuth2Authentication(oauth =>
{
    oauth.ClientId = "your-client-id";
    oauth.Scopes = ["openid", "profile"];
});

// ScalarTheme options: Default, Moon, Purple, BluePlanet, Saturn, Mars, DeepSpace, Kepler, Solarized, Laserwave
options.WithTheme(ScalarTheme.Mars);

// Register multiple OpenAPI documents
builder.Services.AddOpenApi("v1");
builder.Services.AddOpenApi("v2-beta");

// Scalar picks them up automatically
app.MapOpenApi();
app.MapScalarApiReference();
// Available at /scalar/v1 and /scalar/v2-beta

app.MapScalarApiReference(options =>
{
    options
        .AddDocument("v1", "Production API")
        .AddDocument("v2-beta", "Beta API", isDefault: true);
});

// Default is /scalar/{documentName}
app.MapScalarApiReference("/api-docs");
// Now at /api-docs/v1

// When partners need access to docs in production
app.MapOpenApi().RequireAuthorization("ApiDocs");
app.MapScalarApiReference().RequireAuthorization("ApiDocs");

options.ForceDarkMode();

options.WithClassicLayout();

// BAD — anyone can see your API structure
app.MapOpenApi();
app.MapScalarApiReference();

// GOOD — development only
if (app.Environment.IsDevelopment())
{
    app.MapOpenApi();
    app.MapScalarApiReference();
}

// GOOD — production with auth
app.MapOpenApi().RequireAuthorization("ApiDocs");
app.MapScalarApiReference().RequireAuthorization("ApiDocs");

// BAD — real tokens visible in browser
options.AddHttpAuthentication("Bearer", auth =>
{
    auth.Token = "eyJhbG...real-production-token";
});

// GOOD — dev-only test tokens
if (app.Environment.IsDevelopment())
{
    options.AddHttpAuthentication("Bearer", auth =>
    {
        auth.Token = "dev-only-test-token";
    });
}

// BAD — no auth UI in Scalar because OpenAPI doc has no security schemes
builder.Services.AddOpenApi();
app.MapScalarApiReference(options =>
{
    options.WithPreferredScheme("Bearer"); // Does nothing!
});

// GOOD — register the document transformer first
builder.Services.AddOpenApi(options =>
{
    options.AddDocumentTransformer<BearerSecuritySchemeTransformer>();
});
app.MapScalarApiReference(options =>
{
    options.WithPreferredScheme("Bearer");
});

// BAD — auth headers flow through proxy.scalar.com
app.MapScalarApiReference();

// GOOD — disable proxy for APIs with sensitive data
app.MapScalarApiReference(options =>
{
    options.WithProxy(null);
});

// BAD — Swashbuckle removed from templates, maintenance concerns
builder.Services.AddSwaggerGen();
app.UseSwaggerUI();

// GOOD — built-in OpenAPI + Scalar
builder.Services.AddOpenApi();
app.MapOpenApi();
app.MapScalarApiReference();