Strong Password Validation Regex
Uses three lookaheads to require at least one lowercase letter, one uppercase letter, and one digit, then demands 8+ total characters. With the m flag enabled, each line below is validated independently — matching lines pass the policy.
runs 100% in your browser — nothing is uploaded
- 1Paste your textDrop your logs, code, or data into the test box on the right.
- 2Tweak the patternEdit the regex formula or toggle the g / i / m flags on the left.
- 3See matches instantlyMatching text lights up as you type, with a live counter.
//gm
Explanation — token breakdown▾
Matches: 0
Matching runs locally as you type — nothing you paste here leaves this tab.
Expected output — what the pre-loaded example matches
Matches found: 3 (lines that PASS the policy) Correct1Horse ✓ upper + lower + digit, 13 chars sandbox_MAX_2026 ✓ upper + lower + digit, 16 chars Tr0ub4dor&3 ✓ upper + lower + digit, 11 chars Failing: alllowercase1 (no uppercase), ALLUPPERCASE1 (no lowercase), NoNumbersHere (no digit), Sh0rt! (only 6 characters).
This is the result the sandbox above computes from its sample data — edit the pattern, flags, or test string and the live match counter recalculates instantly.