Encode & Hash

URL-Safe Base64 Encoder & Decoder

Encode and decode URL-safe Base64 strings (Base64url). Replaces + with - and / with _ so output is safe in URLs, filenames, and JWT tokens.

Free Client-Side No Sign-Up Nothing Stored
Input text or Base64url string
Output
Output appears here…
Feature Standard Base64 URL-Safe Base64
Characters used +, /, = -, _, (no padding)
URL safe ✗ No ✓ Yes
Filename safe ✗ No ✓ Yes
Used in JWTs ✗ No ✓ Yes
Padding = characters None (omitted)

What This Tool Does

URL-Safe Base64 (Base64url) is identical to standard Base64 except it replaces + with - and / with _, and omits the = padding. This makes the output safe for direct use in URLs, filenames, HTTP headers, and JWT tokens without any further encoding.

Frequently Asked Questions

What is URL-safe Base64?
URL-safe Base64 (also called Base64url) is a variant of standard Base64 that replaces the + character with - and the / character with _. This makes the output safe to include directly in URLs, filenames, and HTTP headers without percent-encoding.
When should I use URL-safe Base64 instead of standard Base64?
Use URL-safe Base64 when the encoded string will appear in a URL query parameter, path segment, or filename, or when working with JWT tokens (which use Base64url for their header and payload sections). Standard Base64's + and / characters have special meaning in URLs and must otherwise be percent-encoded.
Does URL-safe Base64 use padding?
Standard Base64 uses = padding characters at the end to make the length a multiple of 4. URL-safe Base64 often omits this padding since = is also a special character in URLs. This tool outputs without padding by default, matching the JWT and OAuth standards.
Is my data sent to a server?
No. All encoding and decoding happens in your browser. Nothing is transmitted to our servers.