Scalar API documentation UI for .NET 10 applications. Covers setup, themes, authentication prefill, multiple documents, layout options, and security. A modern replacement for Swagger UI. Load this skill when setting up API documentation UI, or when the user mentions "Scalar", "MapScalarApiReference", "API reference", "Swagger UI replacement", "API documentation UI", "Scalar theme", "interactive API docs", or "Try It".
Scalar replaces Swagger UI — Scalar is the recommended API documentation UI for .NET 10. Faster rendering, built-in dark mode, code generation for dozens of languages, and full OpenAPI 3.1 support.
Development only by default — Wrap MapScalarApiReference() in an IsDevelopment() check. API documentation exposes internal structure. If needed in production, add authorization.
Disable the proxy for sensitive APIs — Scalar's "Try It" feature routes through proxy.scalar.com by default. Disable it with .WithProxy(null) to keep auth headers local.
Security schemes come from OpenAPI — Scalar reads security schemes from the OpenAPI document. Configure them via document transformers, not in Scalar directly.
Patterns
Basic Setup
using Scalar.AspNetCore;
var builder = WebApplication.CreateBuilder(args);
builder.Services.AddOpenApi();