Why Swagger is Dead and .NET 9.0 Removed Swashbuckle

The software development landscape is constantly evolving, and tools that once seemed indispensable often fall by the wayside. Swagger, a popular API documentation tool, has recently been deemed outdated by many developers. This shift is reflected in .NET 9.0, which has officially removed support for Swashbuckle, the .NET implementation of Swagger.

Why Swagger is Considered Outdated

Swagger revolutionized API documentation by providing a user-friendly interface for exploring APIs. However, over time, several limitations became apparent:

• Performance Issues: Swagger struggles with large-scale APIs, leading to slow rendering and navigation.
• Limited Customization: While useful, Swagger’s UI offers limited flexibility for modern design requirements.
• Emergence of Alternatives: Tools like OpenAPI and GraphQL provide more robust and flexible solutions.

What Replaces Swashbuckle in .NET 9.0?

.NET 9.0 introduces a shift towards better integration with OpenAPI specifications and native API documentation tools. Key replacements include:

• Minimal APIs: Simplified API structures reduce the need for external documentation tools.
• Native OpenAPI Support: Microsoft has improved OpenAPI integration for seamless API documentation.
• Improved Developer Experience: Features like endpoint summaries and IntelliSense annotations make documentation easier.

Code Example: Using OpenAPI in .NET 9.0

// Enable OpenAPI in your ASP.NET Core application
var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

var app = builder.Build();

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

app.MapGet("/api/hello", () => "Hello, World!")
    .WithName("GetHello")
    .WithOpenApi();

app.Run();

Advantages of Moving Away from Swagger

By phasing out Swashbuckle, .NET developers can benefit from:

• Enhanced Performance: OpenAPI and other alternatives handle large APIs more efficiently.
• Modern Features: Support for advanced configurations and integrations with CI/CD pipelines.
• Better Developer Tools: Native solutions reduce dependency on external libraries.

Conclusion

While Swagger and Swashbuckle have served the developer community well, the move towards modern tools like OpenAPI signifies a natural progression in API development. .NET 9.0’s decision to remove Swashbuckle underscores the importance of embracing more efficient, flexible, and integrated solutions.