URL-safe Base64 for Python

A simple module for encoding without padding, fixing Python standard library's flaws.

Replaces the standard library's base64.urlsafe_b64encode and base64.urlsafe_b64decode with a cleaner implementation that returns strings instead of bytes and avoids unnecessary padding.

Features

• URL safe: Uses only characters that are safe for URLs and filenames
• No padding: Removes trailing = characters for cleaner output
• String output: Returns proper strings instead of bytes (unlike Python's standard library)
• Fast: Based on Python stdlib, with constant-time padding restoration

Installation

pip install base64url

Or for your project using uv:

uv add base64url

Usage

import base64url

text = base64url.enc(bytes(4)) # Returns "AAAAAA"
data = base64url.dec(text)     # Recovers the bytes

enc(data: bytes) -> str

Base64 encode bytes to a URL-safe string without padding.

dec(s: str) -> bytes

Decode URL-safe Base64 into bytes. Padding optional.