The timezone conversions and date arithmetic LLMs get wrong, done exactly. Convert any ISO timestamp or Unix time into one or many IANA timezones (with UTC offset and weekday), add or subtract durations, and diff two instants into days/hours/minutes plus a humanized string. Omit "datetime" to get the current time. Uses the IANA timezone database. POST a JSON body like: {"datetime":"2026-07-08T14:30:00Z","timezone":"America/New_York"}

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