T0x

t0x

T-Zero Timestamp Standard

https://t0x.dev

A fixed-width, unambiguous timestamp format for cross-vendor data exchange.

Format

YYYYMMDDTHHMMSS.sss

Exactly nineteen characters. Fixed-width. No delimiters except the T separator and the dot before milliseconds.

Field	Digits	Range
Year	4	0000-9999
Month	2	01-12
Day	2	01-31 (valid per month)
T	1	literal separator
Hour	2	00-23
Minute	2	00-59
Second	2	00-59
Dot	1	literal separator
Milliseconds	3	000-999 (required)

Rules

1. UTC only. No timezone offsets. All timestamps are UTC.
2. Zero-padded. Every field is exactly its width. No spaces.
3. Milliseconds required. Always three digits, left-padded with zeros. 20260926T154530.001 is 1ms; 20260926T154530.100 is 100ms. On input, shorter fractions may be left-padded (20260926T154530.1 → .001, 20260926T154530.12 → .012). Emitters must always write three digits.
4. No trailing dot. 20260926T154530. is invalid. Omitting milliseconds entirely (20260926T154530) is invalid.
5. Chronological sort. Plain ASCII string sort equals chronological order. No parsing needed. This holds because the form is fixed-width and milliseconds are always three digits in the canonical encoding.

Why

• Unambiguous across locales. Year-month-day ordering eliminates the month/day flip that plagues MM/DD/YYYY vs DD/MM/YYYY.
• Fixed-width. Every field sits at a known byte offset. Truncation shifts the T or the millisecond field and fails validation immediately.
• ASCII-safe. The T separator survives legacy systems, plain-text logs, and pipelines that strip non-ASCII characters.
• Sortable. String comparison gives you time order for free when values are stored in canonical 19-character form.

Examples

20260926T154530.123
20260926T154530.001
20260926T000000.000

Validation

A timestamp is valid if and only if:

• It matches the regex ^\d{8}T\d{6}\.\d{1,3}$ (parsers left-pad ms to three digits)
• Canonical emitted form matches ^\d{8}T\d{6}\.\d{3}$ (exactly 19 characters)
• The date portion is a real calendar date (no Feb 30)
• Hour is 00-23, minute and second are 00-59
• The value is interpreted as UTC

Reference Implementation

See t0x.py in this repository. It provides validate, parse, format, to_epoch_ms, and from_epoch_ms.

Contact

t0x Time Keeper t0xstandard@gmail.com