Cheatsheet Pages / Regex Cheatsheet
A regex for dates in YYYY-MM-DD format
You want the shape of an ISO date checked quickly.
Patterns use the syntax shared by PCRE / Python / JavaScript; engine differences are flagged in the cheatsheet where they matter. Test any pattern at regex101.com — and pick the matching engine.
\d{4}-\d{2}-\d{2}
# matches: 2026-10-09Good to know
This checks the format, not the calendar — 2026-13-99 still matches; validate real dates in code.
