Regex Roulette · #61 · 2026-06-04
Match strings with balanced single parentheses
Difficulty 2/3
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
- (a) — not yet evaluated
- (hello world) — not yet evaluated
- (x) — not yet evaluated
Must not match
- (a — not yet evaluated
- b) — not yet evaluated
- ((a)) — not yet evaluated
- no parens — not yet evaluated
- ()() — not yet evaluated
Loading your progress...
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