How to Use Native OpenAPI in .NET 10 | Replace Swashbuckle with Scalar UI

Published 31/03/2026

Description

The era of Swashbuckle-first setups is changing. With .NET 10, Microsoft has introduced a first-party OpenAPI experience that is faster, cleaner, and specifically optimized for the future of high-performance web APIs and Native AOT scenarios. In this walkthrough, I show you how to move away from the traditional Swagger template and adopt the new Microsoft.AspNetCore.OpenApi package. We will build a Minimal API from scratch, integrate the beautiful Scalar UI for modern interactive documentation, and explore advanced features like multiple OpenAPI documents, document transformers, and full OpenAPI 3.1 support. 0:00 - Introduction 0:10 - Description 1:16 - The Setup (Packages & Configuration) 2:05 - Minimal API OpenAPI Implementation 11:30 - Managing Multiple APIs & Endpoint Groups 17:27 - Advanced OpenAPI & Scalar UI Customization 22:28 - Conclusion What you’ll learn: Native Integration: How to configure the new built-in OpenAPI support in .NET 10. Scalar UI Setup: Creating a professional, interactive developer reference for your APIs. Advanced Document Control: Using document transformers to add descriptions, contact info, and licensing metadata. Multi-Document Support: How to organize and serve multiple OpenAPI documents within the same application. Modern Standards: Leveraging OpenAPI 3.1 features and ensuring your setup is compatible with Native AOT and trimming. This video is essential for .NET developers and architects looking to build lightweight, high-performance microservices using the most modern and future-proof tooling available in the ASP.NET Core ecosystem. #DotNet #OpenAPI #CSharp GitHub https://l.samayas.eu/g7r9PKPR3m Follow me on X: https://l.samayas.eu/jo3eaYEf3E?P=YT&V=106 Buy me a Coffee: https://l.samayas.eu/jX6xL7EWhd?P=YT&V=106 Studio Equipment Camera Sony Alpha ZV-E10 II: https://l.samayas.eu/k7y95TREl0?P=YT&V=106 Secondary Camera Obsbot Tail Air: https://l.samayas.eu/iFQu9WfmCw?P=YT&V=106 Elgato Prompter: https://