jwt-decode VS jose

Now I should mention it's NOT recommended to do this manually. There are great libraries that can help (examples PHP/NodeJS). For the sake of completeness here's how you do it.

A JS library i found for decoding JWT: https://github.com/auth0/jwt-decode

https://github.com/auth0/jwt-decode Again, thanks the developers.

To do all of that, the code would end up looking like that (or any other language alternative) - or you just use a library like jwt-decode. But it is always good to know what they do.

JWT - jose

For demo purpose, we'll use some popular libs e.g. jose.

This module provides a lot of useful functions and utilities, but we will focus only on a couple of them. You can read more about the module itself if you feel like it.

Honestly, not exactly sure what the correct order is. The standard for encrypted jwt is called JWE. Most programming languages will have some kind of library that will handle the small details like order of operations. Example: jose for js.

I used standard Web APIs such as fetch() and WebCrypto. The most common thing I had to do was JWT token generation/validation. I worked with the jose library (the only dependency in the project) because it is cross-platform and also works with the WebCrypto API.

Biggest sharp edge I've encountered is the very much WIP WebCrypto API support. In practical terms, this means things like signing/verifying JWTs is not very well supported: https://github.com/panva/jose/discussions/243

That said, the situation is improving rapidly, and I've been personally willing to bet that the support will be solid by the time I finish prototyping and need to start adding auth to my latest project.