Authentication & Security · In-Browser Regular Expression Lab

Strong Password Regex — Enforce Uppercase, Lowercase, Number & Symbol

Enforces minimum 8 characters, at least one uppercase letter, one lowercase letter, one digit, and one special character.

Pattern:

Regular Expression Pattern & Flags

Flags:

//none

Live Test String

Match Found

Load Sample:

Match Inspection & Details1 match

Match #1:P@ssw0rd2026

Test Samples Verification Matrix

Expected Valid Samples (Should Match)

P@ssw0rd2026 Pass

Secure#Key19 Pass

C@st0vMaster! Pass

Expected Invalid Samples (Must Reject)

password Rejected (Pass)

Password1 Rejected (Pass)

Pass! Rejected (Pass)

short1A! Accepted (Fail)

Code Implementation Generator

// JavaScript / TypeScript (ES6+)
const pattern = /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&#])[A-Za-z\d@$!%*?&#]{8,}$/;
const text = "P@ssw0rd2026";

const isMatch = pattern.test(text);
console.log("Is Match:", isMatch);

if (isMatch) {
  const matches = text.match(pattern);
  console.log("Matches:", matches);
}

Regular Expression Token Breakdown

Uses positive lookaheads to enforce password complexity without consuming characters. Each component of the regular expression serves a distinct syntactical purpose as mapped below:

Token Pattern	Name / Component	Function & Rule
^	Start	Starts at string beginning.
(?=.*[a-z])	Lowercase Lookahead	Requires at least one lowercase character.
(?=.*[A-Z])	Uppercase Lookahead	Requires at least one uppercase character.
(?=.*\d)	Digit Lookahead	Requires at least one number.
(?=.[@$!%?&#])	Symbol Lookahead	Requires at least one special symbol.
[A-Za-z\d@$!%*?&#]{8,}	Length & Allowed Set	Matches allowed character set with minimum 8 length.
$	End	Ends at string finish.