Show HN: AlphaDec, a readable, lexically sortable time format for humans and AI

1 firasd 0 7/19/2025, 6:57:57 PM github.com ↗
I designed AlphaDec, a timezone-agnostic time format that encodes UTC timestamps into chronologically sortable strings like `2025_O2H5_389232`.

The key insight: by dividing the year into 26 periods (A-Z), then subdividing with numbers and letters, you get timestamps that sort naturally as strings while remaining human-readable.

Some practical benefits I've found:

- Perfect as prefixes for database keys

- Time-range queries by truncation (`2024_M` finds everything in that ~14-day period)

- LLM-friendly for log analysis and time-based reasoning

- Glanceable - you can quickly see where in the year a timestamp falls

Interesting emergent property: Periods F, M, S, and Z always bracket equinoxes/solstices, even in leap years.

Live clock: https://firasd.github.io/alphadec/ GitHub: https://github.com/firasd/alphadec

The readme has implementations in JavaScript and PHP. Would love feedback on the concept and where else this might be useful!

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