Password Regex Validator

What is Password Regex in Go?

In Go (Golang), regular expressions (regex) are handled using the regexp package. Password regex is used to enforce password rules such as:

• Minimum and maximum character length

• Required presence of lowercase, uppercase, digits, and/or symbols

• Disallowing whitespace or repeated characters

  
  

Commonly used in:

• Secure user sign-up and login

• Admin panels and dashboards

• API key or token validation UIs

Meta Characters Used in Password Regex

• ^: Anchors the pattern to the beginning of the string

• $: Anchors the pattern to the end of the string

• (?=...): Lookahead to ensure specific characters exist

• [a-z]: Matches any lowercase letter

• [A-Z]: Matches any uppercase letter

• \d: Matches any digit

• [@$!%*?&]: Matches special characters

• {8,}: Enforces a minimum length (e.g., 8 characters)

  
  

How It Works

1. Paste your password regex pattern.

2. Enter the password you want to validate.

3. Click Validate to test the match.

4. Get instant feedback to refine your regex policy.

   
   

Example 1 – Basic Password Validation (8+ chars, 1 uppercase, 1 lowercase, 1 digit)

Use the Go Regex Tester to debug this pattern interactively.

package main

import (
    "fmt"
    "regexp"
)

func isValidPassword(password string) bool {
    var regex = regexp.MustCompile(`^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]{8,}$`)
    return regex.MatchString(password)
}

func main() {
    password := "Secure123"
    fmt.Println("Valid password:", isValidPassword(password))
}

Example 2 – Include Special Characters

Need help generating secure passwords? Use the Password Generator for testing combinations.

var strongPattern = regexp.MustCompile(`^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$`)
fmt.Println(strongPattern.MatchString("Test@1234"))

Example 3 – Restrict Whitespace and Repeating Characters

Pair with the Username Generator to test login form validations.

var strictPattern = regexp.MustCompile(`^(?!.*\s)(?!.*(.)\1{2,})(?=.*[a-z])(?=.*[A-Z])(?=.*\d).{8,}$`)
fmt.Println(strictPattern.MatchString("Pass1234"))

Pro Tips for Password Regex

• Use (?=.*[a-z]) style lookaheads to enforce mixed character types.

• Avoid .* unless necessary; it can allow bypasses if misused.

• Add {min,max} for exact length control.

• Combine with special character groups to enforce symbol use.

• Always anchor your regex using ^ and $ to prevent partial matches.

  
  

Combine with These Tools

• Username Generator – Create mock user accounts for auth testing

• Email Regex Go Validator – Verify valid emails during signup

• Phone Number Generator – Populate contact fields with dummy data

• API Key Generator – Secure backend API testing alongside password validation

• Token Generator – Simulate auth flows with passwords and tokens

  
  

Use Cases

• Sign-up and login form validation

• Secure password creation interfaces

• Admin panel access control

• Two-factor or multi-factor password pre-validation

• Password update/reset workflows