Regex Roulette · #38 · 2026-05-12
Match 2-digit hexadecimal byte values (00–FF, case-insensitive)
Difficulty 1/3
How to play
Write a regex that matches all green strings and rejects all red strings. Live feedback shows which strings pass. Shorter patterns score better.
Must match
- 00 — not yet evaluated
- FF — not yet evaluated
- ab — not yet evaluated
- 1A — not yet evaluated
- 0f — not yet evaluated
Must not match
- 0 — not yet evaluated
- FFF — not yet evaluated
- GG — not yet evaluated
- xyz — not yet evaluated
- 0x1A — not yet evaluated
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Pattern body only — slashes and flags (e.g. /g, /i) aren't part of the input.
0/200 chars
Type a regex that matches all green strings and rejects all red strings · Back to hub