(essentially MAL-Stalker)
MAL-User2ID (or MAL-Stalker) is a tool to convert MyAnimeList usernames to user-ids and vice versa. Each user has a fixed unique ID that cannot be changed, though usernames can be changed at most once every month, making it difficult to stalk your most favourite MAL user who frequently changes his username. ^ω^
The tool also saves the recorded username and its corresponding ID, and the date it has first recorded each username for a certain profile.
The application also includes the option to search a username in its past logs, to view all the users who have been seen (queried by the tool) using this username before.