Tutorials ASP.NET Core Web API Tutorial
SSO Authentication in ASP.NET Core Web API — Complete Guide
SSO Authentication in ASP.NET Core Web API — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of ASP.NET Core Web API Tutorial on Toolliyo Academy.
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ASP.NET Core Web API Tutorial · Lesson 149 of 175
SSO Authentication in ASP.NET Core Web API
Beginner ✓ → Intermediate ✓ → Advanced → Professional
Advanced · 3 — Security & patterns · ~10 min · Module 13: Security
What is this?
Single Sign-On lets users log in once and access ShopNest.API, admin MVC, and partner apps without separate passwords.
Why should you care?
Enterprise customers demand SSO with Azure AD, Google Workspace, or Okta.
See it live — copy this example
Create a Web API (dotnet new webapi), paste the example, run dotnet run, test in Swagger.
builder.Services.AddAuthentication(OpenIdConnectDefaults.AuthenticationScheme)
.AddOpenIdConnect(options => { options.Authority = "https://login.microsoftonline.com/tenant"; });
Run Example »
Edit the code and click Run — like W3Schools Try it Yourself.
What happened?
- Auth server issues tokens; resource APIs validate JWT; MVC clients redirect to login once.
- Follow the practice steps below on ShopNest.API — typing code yourself is the fastest way to learn.
Try it yourself
- Read the real-world section and name which part of ShopNest.API uses this topic.
- Run dotnet run and test the endpoint in Swagger UI or curl.
- Change one value in the example (route, DTO field, or status code) and predict what will happen before you save.
- Change a route URL or DTO property and save — test again in Swagger or curl.
- Return the wrong status code on purpose (404 instead of 200) and see what the client shows.