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.

Want to dive deeper? You can also open your regex in a dedicated editor for more advanced debugging and fine-tuning. This lets you visualize matches, experiment with variations, and ensure your pattern meets every requirement before deploying it in your application. Whether you're just checking a quick pattern or doing detailed analysis, these tools help streamline the process and catch issues early.

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 – Strict Password Validation in ECMAScript (JavaScript)

Want to enforce a robust password policy in your JavaScript applications? Use a pattern that covers all the essentials:

• At least one digit (0-9)

• At least one uppercase letter

• At least one lowercase letter

• At least one special character (non-alphanumeric)

• No spaces allowed

• Total length between 8 and 16 characters

Here’s a regex that brings these rules together for ECMAScript:

/^(?=.*\d)(?=.*[A-Z])(?=.*[a-z])(?=.*[^\w\d\s:])([^\s]){8,16}$/

How it works:

• (?=.*\d): Ensures at least one digit is present.

• (?=.*[A-Z]): Requires at least one uppercase letter.

• (?=.*[a-z]): Requires at least one lowercase letter.

• (?=.*[^\w\d\s:]): Checks for at least one special character.

• ([^\s]){8,16}: Limits the password length and disallows spaces.

For easier testing, check your passwords against this pattern in modern code playgrounds and tweak as needed for your login or signup flows.

Example 4 – 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"))

Filter by Regex Flavor

To help you tailor your patterns and ensure compatibility across different platforms, you can filter password regexes by popular programming language flavors, including:

• ECMAScript (JavaScript)

• Python

• Go (Golang)

• Java 8

  
  

Switch between these flavors to match the syntax and features specific to your language of choice. This way, you can be sure your regex will behave exactly as intended, no surprises when moving between backend and frontend codebases.

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