I am writing a plugin that fetches some extended user info from a remote service and I need it to execute its function each time a user logs in.
Is there a hook that gets fired after login that I can add an action to?
The action hook wp_login runs when the user logs in - it can run a simple function.
The real breadwinner here is wp_authenticate which has a bit of documentation. It passes an array with the given username and password, which gives you the opportunity to pass info to the remote service, if necessary.
I would caution against using wp_login. It is depreciated and in later versions of wordpress it may not work at all. Instead try, wp_sigon.
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