No rate limit for users/lookup with Application Only


My users signup exclusively via Twitter. Once per day I like to update their profile information which is pulled from their Twitter profile. (i.e: screen_name, name, proflile_pic, timezone).

Right now I’m using /users/lookup to update my 40,000+ user profiles at night and I do this via Application Only authentication (using just the application “consumer token” and “consumer secret”).

What I’ve noticed is that there is no rate limiting what so ever. The headers also lack the “X-Rate-Limit” as well. According to the API docs there should be a rate limit for this resource.

Is there something I’m not seeing? I want to verify that my application isn’t going to be black-listed for updating the user profile information each night.