Personality Engine, built for a client and scaled to millions

A personality reading platform built for a client, where users enter an X username and receive a deterministic, calculated result — no quiz questions, no accounts, no randomness.

Built entirely in vanilla JavaScript with no framework dependency, and fully static with no backend or database. The username is deterministically mapped to a result client-side, letting the site scale to over 1.5 million monthly visitors at its peak with zero server infrastructure or hosting cost. I handled ongoing maintenance, feature updates, and traffic monitoring solo.