leap-second

An overflow-safe, high-performance datetime library providing leap-second-correct nanosecond precision across UTC, GPST, and relativistic time-scales. Flight-proven in lunar and deep-space missions.

Find the next leap second using IERS-OP web service.

Re-run a test suite with the clock moved to dates human intuition misses, and report which ones fail.

A leap-second lab: TAI, UTC, GPS, Unix and UT1 on one timeline, a leap second replayed through stepping, smeared and monotonic clocks, what JS, Python and Postgres do with 23:59:60, and fix-the-bug exercises. Built with Claude Code.

A high-performance Python library for parsing and analyzing the IANA Time Zone Database (tzdb). Built for production use with smart caching, minimal dependencies, and a practical API.

Faithful, memory-safe Rust port of upstream leapseconds.awk — generates the zic 'leapseconds' source from NIST/IERS leap-seconds.list, byte-identical to the awk oracle.

Live UTC/TAI/GPS clock comparison and a countdown to the December 2026 leap-second decision, with the odds and the reasoning.

A python library for handling precise date/times, virtually infinitely far into the past and future, including support for leap seconds and partial support for timezones.

Public UTC is a free, no-log public NTP time service with Network Time Security (NTS, RFC 8915). Use smear.public-utc.com (recommended) or leap.public-utc.com. IPv4 and IPv6.

Rust date time library with astronomical and civil timekeeping. Parse dates, parse relativate dates, format, time scales, leap seconds, attosecond precision, and much more