Keycloak VS IdentityServer

For Authentication and Authorization, I use FreeIPA for LDAP and Keycloak for OAuth2/OpenID Connect. The FreeIPA client automatically pulls my public SSH key into whichever server I sign in to, so I never need to enter my password from my primary PC.

In the end, I developed a stack that I liked and re-used across multiple projects, which consisted (mostly) of Postgres, Hasura, Nest.js, Keycloak, and Next.js or Expo. More recently I've started moving away from Keycloak towards Ory Kratos/Oathkeeper. In certain cases, I also deployed AppSmith and Metabase and I considered tools like Meilisearch in a couple instances.

It depends on what context you're operating in. The reality is that most people don't fully understand authentication / authorization properly so they often mess up. When you have a small team of engineers that are spread very thin, it might be better to delegate this responsibility. If you have the time and resources to study the topic in depth and implement it properly then it's fine. It's just not that interesting of an area since the space for innovation and creativity is limited, and since the major problems have already been reliably solved by others at best you end up with an equivalent outcome and at worst you end up with security issues.

If you're operating within an enterprise context, Keycloak [0] is pretty massive but provides comprehensive coverage for all authN and authZ needs, and it's open source.

Back when I first started studying this topic I found that reading through a lot of NIST guidelines was helpful. I'd recommend at least browsing through SP 800-63-3 [1], SP 800-63A, SP 800-63B, SP 800-63C to get a good idea of the domain. Admittedly, this might be a lot of overkill for your application and needs.

[0] https://www.keycloak.org/

About Desktop OAuth protocol, you could try doing something as a "localhost" server... like Keycloak's (an IAM provider) folk did here: https://github.com/keycloak/keycloak/tree/main/adapters/oidc/installed

I think Duende (Identity Server) handled the situation pretty well.

https://duendesoftware.com/products/identityserver

> Standard License Pricing

Thanks for your message. No, the idea was not to re-implement OAuth nor OpenID stuff. What I had in mind for the authentication thingy was something like this: https://laravel.com/docs/9.x/sanctum. If we want to go the OAuth/OpenID way, in .NET we have this one: https://github.com/DuendeSoftware/IdentityServer.

> As you said, there are plenty of local options that you only need to run.

I think managed databases are a good analogy here. While I might run my own PostgreSQL/MariaDB instance, many out there won't be overjoyed at the idea of actually needing to run and manage the damned thing, as well as set up some kind of alerting and handling the need to eventually scale it up.

> It also has the largest risk of compromise and data leaking from any service you may use...

PII is definitely a big concern, even if something like password hashes aren't too useful on their own (provided that they're salted), though in cases like that it might actually make a lot of sense to utilize a widely used and tested solution that's specialized for this particular use case.

In many cases, thousands of people across the globe will be able to develop something and squash any bugs in it better than you might be able to do individually or with your own team, though there might be a few exceptions out there. Auth is probably not one of the cases where you want to write code without a lot of eyes on it.

> ...the largest amount of potential lock-in...

This is debatable: standards like OAuth2 and OIDC technically make many of the solutions and libraries way more pluggable and make it easier to choose between various implementations, depending on your needs.

Of course, something like Keycloak also has its own API (as do many of the cloud offerings) so if you build too much automation around a particular implementation, then that advantage partially goes out the window.

> ...and the least need for integration.

I'm not sure about this, it probably depends on your architecture. If you have a monolithic web app, then you probably don't need a separate turnkey/SaaS solution, whereas if you have an ever growing number of services, whilst you want to manage authentication and accounts against all of them centrally, then something like Keycloak (or one of the cloud alternatives) become way more lucrative.

That said, I'd still opt for self-hostable options whenever possible, albeit I also don't trust cloud based password managers and such, preferring something like KeePass instead. I've probably just come to a different conclusion in regards to usability/responsibility/features/security than some other people.

Sadly, there aren't that many good options out there at the moment, apart from Keycloak. For example, IdentityServer is promising, but went in a commercial direction: https://duendesoftware.com/products/identityserver#pricing

He's referring to IdentityServer 3/4, which was open sourced, and was not owned by Microsoft. That 3rd party is commercializing their work (and to be fair, it's a lot of work) as https://duendesoftware.com/products/identityserver , and has a different commercial licensing model.

https://github.com/DuendeSoftware/IdentityServer/blob/main/L... does not seem to square with any definition of "open source" I'm familiar with, and that goes double for having an in-repo file that just says "read this unversioned pdf on some other site"

I think "Identity Provider" is more correct, no? "IdentityServer" is the name of a specific IdP implemented in .NET (formerly OSS as https://identityserver4.readthedocs.io/en/latest, and now as a more commercial form as Duende IdentityServer: https://duendesoftware.com/products/identityserver)

I would not recommend it. There is a server named Duende identity server which you can host locally.

That repository is now (effectively) dead and the new home is over at https://github.com/DuendeSoftware/IdentityServer along with their new license. Here's a recent discussion on the change: https://old.reddit.com/r/dotnet/comments/s1bplx/duende_moves_to_a_new_fair_trade_license_lifting/