What is the regex for jwt token?

The regex pattern for jwt token is `^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$`. This pattern validates json web token (header.payload.signature).

How do I use this regex in JavaScript?

In JavaScript, create the regex with `const regex = /^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$/;` and test with `regex.test(yourValue)`. It returns `true` if the value matches.

How do I use this regex in Python?

In Python, use `import re; re.match(r'^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$', value)`. The raw string prefix (`r`) prevents Python from interpreting backslashes as escape characters.

Is this regex case-sensitive?

By default, yes. To make it case-insensitive, add the `i` flag in JavaScript (`/^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$/i`) or use `re.IGNORECASE` in Python.

Regex for JWT Token

Regex Pattern

^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$

JSON Web Token (header.payload.signature)

Quick Answer

The regex pattern for jwt token is `^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$`. JSON Web Token (header.payload.signature). This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

Input	Result
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c	✓ Matches
notajwt	✗ No match
header.payload	✗ No match
header.payload.signature.extra	✗ No match

Code Examples

javascript

const regex = /^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$/;
const isValid = regex.test(value);

python

import re
pattern = r'^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^[A-Za-z0-9-_]+\.[A-Za-z0-9-_]+\.[A-Za-z0-9-_]*$/', $value)) {
    echo "valid";
}

java

String pattern = "^[A-Za-z0-9-_]+\\.[A-Za-z0-9-_]+\\.[A-Za-z0-9-_]*$";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

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