Daily Regex Golf.

One puzzle for everyone, every day. Seeded by UTC date — same challenge worldwide. Write the shortest regex that matches all targets and rejects all forbidden words.

seed

2026-07-14

puzzle

#22

optimal

18 chars

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Puzzle #22 — Hex Color

optimal: 18 chars

// Target — must ALL match

#FF0000#1a2b3c#aAbBcC#000000

// Forbidden — NONE may match

#GG0000red#12345#1234567

Your regex

Tip: tap and hold keys or use the Regex Chars toolbar for special characters

each active flag adds 2 chars to score

Score: — chars

Optimal: 18 chars

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how it works

Score = character count of your regex. Shorter is better. Each active flag (i, m, s) adds 2 chars.

safety

Regex runs in a sandboxed Web Worker with a 100ms timeout. Catastrophic backtracking can’t freeze your tab.

resets

Daily puzzle resets at 00:00 UTC. Refresh after midnight to play the next puzzle. Progress saved locally.