About

SummaryLog is a collection of free, fast, privacy-friendly tools for developers and for everyday life in Japan.

Every tool runs entirely in your browser with no sign-up, no tracking of the content you enter, and no external dependencies. We built each utility to do one thing well and to load instantly.

The toolset includes developer utilities (JSON, Base64, hashing, regex, JWT, and more) and practical life-in-Japan tools (payslip and tax estimation, visa timelines, moving checklists).