> [...] you don't actually need to verify agains a user's secret immediately, you simply need to check that the token is valid using the app secret. The subset of valid tokens that you need to check is much smaller than the universe of all the unexpired tokens your application has issued.
What you are describing here is different than what is described in the blog post that you linked to.
Please look at the definition of the function 'validateToken'. In particular, notice how 'getUser' function (which the author notes issues a DB query) is called for every JWT with a valid signature!
EDIT: I failed to realize that you are the author of the blog post. Still my point stands, in that your description doesn't match what the code does.
Maybe I should add a comment there, but this is a compressed example. Everything from getUser onwards does not need to be in the validateToken, it can be done downstream, closer to where you access user data. It does not need to be a separate db call, You pull a user and want to perform an action, so data is in memory, use the secret from there.
Or if you are doing inter service communication, you can use your app secret to validate that the token can actually cross your infra boundary (no user query here), and each internal service can then validate it in their scope, or if a passthrough (like a proxy), just forward it like an envelope.
What this does is give you 2 secure layers, therefore saving you from a lot of the compute (drop expired and globally invalid tokens at the boundary), kill db round trips meant only for token validation (attach to an existing user query you already do) and kill revocation list management.