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
- Urlsafe: 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, *, validate=True) -> bytes
Decode URL-safe Base64 into bytes. Padding optional. Set validate=False to silently ignore any unknown characters (Python base64 default behavior).
enc_lines(data: bytes, length: int = 76) -> str
Encode with newlines inserted every length characters.
dec_lines(s: str) -> bytes
Decode formatted input, ignoring all whitespace (but not other unknown characters).