I think I've found a bug when using the /users/lookup.json API call and supplying the oAuth headers as querystring parameters.
My code generates both forms of oAuth header so I can test (regular Authorization: style and the querystring kind) Using an API call like /friends/ids.json is fine using querystring oAuth params: curl -v -H 'Accept: application/json' 'https://api.twitter.com/1/ friends/ids.json?user_id=60173&realm=https://api.twitter.com/1/friends/ ids.json&oauth_consumer_key=KKK&oauth_token=TTT&oauth_nonce=601731307115467&oauth_timestamp=1307115467&oauth_signature_method=HMAC- SHA1&oauth_version=1.0&oauth_signature=SSS%3D' But for /users/lookup.json it fails with an "Incorrect signature" error: curl -v -H 'Accept: application/json' 'https://api.twitter.com/1/users/ lookup.json?user_id=60173&realm=https://api.twitter.com/1/users/ lookup.json&oauth_consumer_key=KKK&oauth_token=TTT&oauth_nonce=601731307115963&oauth_timestamp=1307115963&oauth_signature_method=HMAC- SHA1&oauth_version=1.0&oauth_signature=SSS%3D' (where KKK, TTT & SSS are placeholders for my actual values) If I use Authorization headers, rather than querystring params for the oAuth data, then everything is fine: curl -v -H 'Authorization: OAuth realm="https://api.twitter.com/1/ users/ lookup.json",oauth_consumer_key="KKK",oauth_token="TTT",oauth_nonce="601731307115963",oauth_timestamp="1307115963",oauth_signature_method="HMAC- SHA1",oauth_version="1.0",oauth_signature="SSS%3D"' https://api.twitter.com/1/users/lookup.json?user_id=60173 I thought it might initially be because I was using HTTPS urls rather than HTTP, but the result is the same. For the /users/lookup.json API call, using either HTTP or HTTPS and supplying the oAuth headers as querystring parameters, you will always receive an "Incorrect signature" error. The only way to call this method is by supplying the oAuth values as Authorization headers. This is a problem for me, as I need to call the /users/lookup.json as JSONP and I can't supply the headers other than as querystring parameters. -- Twitter developer documentation and resources: https://dev.twitter.com/doc API updates via Twitter: https://twitter.com/twitterapi Issues/Enhancements Tracker: https://code.google.com/p/twitter-api/issues/list Change your membership to this group: https://groups.google.com/forum/#!forum/twitter-development-talk
