The Klout API is designed to return influence metrics generated by Klout. The Klout REST API returns these metrics in XML or JSON.

We have 3 API methods you can use:

1. Klout (GET/POST)
GET:http://klout.com/api/twitter/1/klout/[user_key]/twitter_screenname.[return_type]: This method allows you to retrieve a Klout score in XML or JSON with [return_type] as “xml” or “json”.
POST:http://klout.com/api/twitter/1/klout/[user_key]/: This method allows you to retrieve a Klout score in bulk by POSTing a list of Twitter usernames in JSON. Up to 100 usernames can be requested.

2. Profile Detail (GET)
http://klout.com/api/twitter/1.1/profiledetail/[user_key]/twitter_screenname.[return_type]: This method allows you to retrieve Klout’s influence metrics in XML or JSON with [return_type] as “xml” or “json”. If a score is not found for the user, they are automatically placed into Klout’s queues for processing and a 202 (Accepted) is returned.

3. Profile Request (POST)
http://klout.com/api/twitter/1/[userkey]/profilerequest.[post_type]: This method allows you to send Klout a list of usernames that for Klout to start processing. [post_type] refers to either XML or JSON. For JSON posts, a JSON string is expected in a variable named “users”.