Create a website to login in with Gmail, Yahoo, or Facebook accounts

Question

How does Stack Overflow allow new users to login into Stack Overflow using their Gmail or Facebook or Yahoo accounts? I am working on a little project website and I was curious how Stack Overflow does this. Do I need to get permission from these companies to do this or can I just do it?

Solution 1

StackOverflow (and all other StackExchange sites) use OpenID.

OpenID is a decentralized authentication protocol that makes it easy for people to sign up and access web accounts.

Yahoo, Google and facebook are all OpenID providers, so simply implementing it on your site will be enough for your users to be able to login using them (and any other OpenID provider).

There is no need to get permission - the permission will be gotten by the users of your application.

Solution 2

You can "just do it" using OpenId. That's what StackOverflow uses.

Solution 3

There are libraries available for Java Python, PHP, and others. Google authentication has been tested against the OpenID for Java library; see also libraries at OpenID Enabled. A comprehensive list of libraries is available on the OpenID site. For developers using OpenID for Java, this quick-start guide covers how to set up as an OpenID relying party. You may also use an implementation provided by a third-party such as JanRain

Comments

[milan]

Are there any good tutorials that you would recommend to implement this on my site? I was hoping a plugin for joomla! existed, but it doesn't look like it does.

[Oded]

@milan - I don't know joomla. I would look for an OpenId library for your platform - there should be at least an example included.

[Alex Hope O'Connor]

Looking at this page openid.net/get-an-openid, it does not look like Facebook offers OpenID?

[Oded]

@AlexHopeO'Connor - They may have dropped it.