Regex for JWT Token

Validates JSON Web Token format: three Base64url-encoded segments separated by dots.

Pattern

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

Live Tester

Enter a string to test

Examples

✓ eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U

✓ abc.def.ghi

✓ header_1.payload-2.signature_3

✗ abc.def

✗ abc.def.ghi.jkl

✗ abc def.ghi.jkl

Pattern Breakdown

^[A-Za-z0-9_-]+ — Base64url-encoded header

\.[A-Za-z0-9_-]+ — dot + Base64url-encoded payload

\.[A-Za-z0-9_-]+$ — dot + Base64url-encoded signature

Code Snippets

Javascript

const regex = /^[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+$/;
regex.test("eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxIn0.rq8ssgv0jX0Hz"); // true

Python

import re
pattern = r"^[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+$"
bool(re.match(pattern, "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxIn0.rq8ssgv0jX0Hz"))  # True

Php

$pattern = '/^[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+\.[A-Za-z0-9_-]+$/';
preg_match($pattern, "eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxIn0.rq8ssgv0jX0Hz"); // 1

Related Patterns

Email Address /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/ URL /^https?:\/\/(www\.)?[a-zA-Z0-9@:%._+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([a-zA-Z0-9()@:%_+.~#?&/=-]*)$/ Phone Number (International) /^\+?[1-9]\d{1,14}$/ Phone Number (US) /^$?[2-9]\d{2}$?[-.\s]?\d{3}[-.\s]?\d{4}$/ Phone Number (EU) /^\+?[1-9][0-9]{0,3}[\s.-]?$?[0-9]{1,5}$?[\s.-]?[0-9]{1,5}[\s.-]?[0-9]{1,5}$/ IPv4 Address /^((25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(25[0-5]|2[0-4]\d|[01]?\d\d?)$/

Frequently Asked Questions

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_-]+$/. Validates JSON Web Token format: three Base64url-encoded segments separated by dots.

How do I use the JWT Token regex in JavaScript?▾

In JavaScript you create the pattern with a regex literal or the RegExp constructor and call .test() to check a string against it. A ready-to-copy example is shown in the Code Snippets section above, alongside Python and PHP versions.

What does the JWT Token pattern match?▾

It matches strings like eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjM0NTY3ODkwIn0.dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U; it rejects strings like abc.def. See the Examples section above for the full list of matching and non-matching cases.