Is the code that validates service stack licenses part of the open source? Was hoping to leverage a similar commercial model for some of my apps. If not, understand, wondering if anyone has any suggestions for validating an expiring key.

You can use the source code under the same commercial license you’re using ServiceStack NuGet packages with, so you will be able to use it in your commercial products. The license code starts from LicenseUtils but it’s very much tied to ServiceStack and not in a reusable form so I don’t know how much value you would get from trying to use it.

If I had to implement it again I would probably use an encrypted JWE Token rather than a custom format. This is the code we use for validating a JWE Token whilst this is the code for generating one.