I saw some data on internet that showed this info at the individual level. Is such data available to public to download?
Are you asking about the United States? If so, you are probably not going to find it all for download in one place. That is because public employee information has to be requested from each individual government unit (state, county, or city).
Several sites have done this for entire states. Many of them do allow downloads. Some examples in no particular order (Googled "public employees salaries"):