Identity Server: API Migration to ASP.NET Core 2

After writing the basic migration guide from ASP.NET Core 1.1.x to 2.0 I embarked on the task of upgrading the rest of the projects I have on GitHub. For the most part, it has been a pretty smooth transition. This post is going cover the differences that I hit while converting an API that is part of my IdentityServer sample project. This assumes that you have already followed my other migration post which can be found here.

Package Changes

The source of this conversion being different is that the IdentityServer4.AccessTokenValidation NuGet package is not currently supported on ASP.NET Core 2. Token validation can be done using bits provided by the framework. This is the recommended path suggested by the IdentityServer team as posted on this issue. Longer term you may want to switch back if you have a need for more features not provided by the Microsoft implementation as pointed out in this issue.

As for the actual change, just remove the reference to IdentityServer4.AccessTokenValidation from your project using the NuGet UI, Package Manager Console, or by editing the csproj file.


All the rest of the changes are in the Startup class. First, in the Configure function app.UseIdentityServerAuthentication gets replaced with app.UseAuthentication.

app.UseIdentityServerAuthentication(new IdentityServerAuthenticationOptions
    Authority = "http://localhost:5000",
    RequireHttpsMetadata = false,
    ApiName = "apiApp"


In the ConfigureServices function is now where JWT Bearer options are set up. First, we have to add the type of authentication the API is going to use and then the options for JWT Bearer are set, which will match the settings that were being used before with the IdentityServer package.

services.AddAuthentication(options =>
    options.DefaultAuthenticateScheme = 
    options.DefaultChallengeScheme = 
}).AddJwtBearer(o =>
    o.Authority = "http://localhost:5000";
    o.Audience = "apiApp";
    o.RequireHttpsMetadata = false;

Wrapping up

With the above, your API can run on ASP.NET Core 2 and still verify authorization using IdentityServer4. My IdentityServer sample project is taking the longest to update so I would expect at least one or two more posts on the process as each of the projects gets upgraded.

4 thoughts on “Identity Server: API Migration to ASP.NET Core 2”

  1. Thank you for this. After long searching this was finally the solution I needed; the standard microsoft documentation did not include how to convert the AddJwtBearer related code which you just posted.

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