Password (No Special Chars) in GO
Go (RE2) can't run this pattern out of the box.
Try it in the GO tester →Why it doesn't work in GO
Go's RE2 engine doesn't support lookarounds (`(?=...)`, `(?<=...)`, etc.) — they break the linear-time matching guarantee.
Workaround
Restructure to capture the surrounding context as a group instead, or use JS / Python where lookarounds are available.
Pattern
regexGO
^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[A-Za-z\d]{8,}$How the pattern works
Three positive lookaheads (?=.*[a-z]) (?=.*[A-Z]) (?=.*\d) require a lowercase letter, uppercase letter, and digit somewhere in the string. [A-Za-z\d]{8,}$ then matches 8+ alphanumerics. Lookaheads are zero-width so they don't consume — they're constraints, not consumers. Note: Go's RE2 does not support lookaheads, so this pattern won't compile there.
Examples
Input
Password1Matches
Password1
Input
MyPass99Matches
MyPass99
Input
weakpassNo match
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