This is a very simple database with a web interface that records all username changes in OpenStreetMap.

There is a parse_osc.pl script. If you run it with -c key, it will create a table in a specified database. To populate that database, you would need to parse every replication diff since the dawn of the OSM (the latest changeset dump won't do: it contains only the latest user names). After that just set up hourly replication. Parameters of the script are identical to the similar named one in WHODIDIT project.

You can download database backup here. Number in the file name denotes sequence index which you should put into state.txt when using hourly updates. This file is updated very seldom: replication diffs are processed very fast, so there's no need.

There is an API at http://textual.ru/whosthat/whosthat.php. It returns JSON or JSONP (if you specify jsonp=<name> parameter). It has following actions:

• action=last: returns the last username for specified users. It's an array of strings.
• action=names: returns all names for specified users, sorted by date. It's an array of hashes: id for user id and names for an array of user names.
• action=info: returns detailed information on name changes for specidied users. It's an array of hashes: id and names, the latter contains array of hashes with name for user name, first for the first spotted usage in database and last for the last one.
• action=recent: returns 15 last renamings. It's an array of hashes with id, date, from and to keys.

To specify users, use one of those parameters:

• id=<user_id>: query by user id.
• name=<user_name>: query by user name. Note that there can be several matches.
• q=<query_string>: search all users whose name matches the query string.

All this is written by Ilya Zverev and licensed WTFPL: do whatever you want with it.