YARP VS IdentityServer

YARP is highly customizable, allowing you to implement advanced routing strategies, add middleware for logging and authentication, and even configure load balancing algorithms. For more information, you can refer to the official YARP documentation.

Adding to the other answers here, you might find some useful functionality in YARP if you want a pure .NET reverse proxy. Like Kestrel, Microsoft dogfoods YARP in Azure.

➡️ Release 2.0.0-RC.1 · microsoft/reverse-proxy · GitHub ➡️ Visual Studio 2022 17.5 Preview 3 is here!

In your application, you may be using YARP, to build a reverse proxy gateway sitting in front of various backend applications. For example, you may run YARP to listen on example.org, and have it proxy all requests going to this domain while mapping /api and /docs to different web apps running on diffreent servers.

Microsoft already made YARP for their Azure infrastructure, it's a "build your own reverse proxy" kit.

If I was to need one I would probably reach for YARP (Yet Another Reverse Proxy) from MS. https://microsoft.github.io/reverse-proxy/

Its deprecated in favor of Duende Identityserver which introduced a license model.

Tokens usually have a lifetime and they are separate from the user's authentication principals like username and password. Unless you are rolling your own form of token provider (not something that would be recommended) the token creation is handled for you. Take a look at https://identityserver4.readthedocs.io/en/latest/ or if your organization makes under 1M in income a year the free version of what Identity Server progressed into https://duendesoftware.com/products/identityserver

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