Item — HN Reader

> Fair enough, but those optimizations are basically free. People think stateless tokens are free but they really are not.

Strawman.

The only requirement for a JWT is posting the JSON Web Key set with the public keys used to verify the JWTs signature. That's the full cost of a no-frills JWT implementation of you exclude IAM.

If you want to have one-time JWTs you need to maintain a revocation list. This is literally a set of IDs. If you go nuts and use GUIs for JWT IDs that means each entry takes as much space as 4 ints, and all you need is a set membership check on said integer. Even at FANG scale you can handle that scale in a memory cache service such as ValKey running on a COTS desktop.

Now show us your alternative.

2 comments

Yes we have heard this before, React is only 30kb! But that misses the enormous amount of infra you need to even just do a basic fetch. (Read the post by the React Query author on whether you need React Query or not)

Likewise with JWTs for sessions you need to handle cache invalidation, revocation lists, key rotation, the list of difficult comp sci problems really does go on!

The same issue as always plaguing the frontend world. Up front “simplicity”, enormous actual complexity

> Yes we have heard this before, React is only 30kb!

Not quite. You might be surprised to know, but the whole JOSE standard, and JWT in particular, specify a very limited set of fields. Whenever anyone starts requiring more than that, the responsibilities start to be offloaded to the likes of OpenID Connect.

For those curious, here are the relevant specified fields along with the relevant standards (both IETF, OIDC, etc)

JWT: https://www.iana.org/assignments/jwt/jwt.xhtml

JOSE: https://www.iana.org/assignments/jwt/jwt.xhtml

This is actually really funny because I recently had this problem having to authenticate an internal repo with an OIDC but the script had to run so early in the bootstrap processes that the python google sdk is not yet installed so I had to manually install the SDK before apt is available by pulling it down manually to bootstrap the chicken or the egg problem. My initial implementation was using curl but folks insisted (rightly) on using the official SDK. I'm sure it's a lot more than 30kb though not during runtime per say.

> If you want to have one-time JWTs you need to maintain a revocation list.

No, you always need a revocation list if you want to handle user sessions in a secure manner. What claims do your tokens contain? If it's anything other than some stable identifiers, like user name, email, permissions, etc. then you now have a cache invalidation problem.

But if all your token carries is an identifier which you need to look up, how's this any better than a signed cookie containing the session ID? All you've done is add complexity.