A tiny project to avoid a major head ache.

.gitignore

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+__pycache__/
+dist/
+.*
+!.gitignore

README.md

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+# 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
+
+```sh
+pip install b64url
+```
+
+Or for your project using [uv](https://docs.astral.sh/uv/):
+```sh
+uv add b64url
+```
+
+## Usage
+
+```python
+import b64url
+
+text = b64url.enc(bytes(4))  # Returns str "AAAAAA"
+data = b64url.dec(text)      # Returns the original bytes
+```
+
+### `enc(data: bytes) -> str`
+
+Encode bytes to a web-safe Base64 string without padding.
+
+### `dec(s: str) -> bytes`
+
+Decode a web-safe Base64 string to bytes. Padding is optional.

b64url.py

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+"""URL-safe Base64 encoding without padding.
+
+This format uses only characters that are safe for URLs, filenames etc.
+Refer to Python's urlsafe_b64encode and base64.urlsafe_b64decode for more details.
+
+Fixes Python base64 module's faults:
+- Padding "==" is optional and not produced by b64url.enc
+- Base64 type is str (stdlib is retarded and uses bytes)
+- Otherwise identical to urlsafe_b64encode/urlsafe_b64decode
+"""
+
+from base64 import urlsafe_b64decode as _decode
+from base64 import urlsafe_b64encode as _encode
+
+__all__ = ["enc", "dec"]
+
+
+def enc(data: bytes) -> str:
+    """Base64 encode bytes to a URL-safe string without padding."""
+    return _encode(data).decode("ascii").rstrip("=")
+
+
+def dec(s: str) -> bytes:
+    """Decode URL-safe Base64 into bytes. Padding optional."""
+    # Testing whether needs padding is slower, this is the fastest way and constant time.
+    return _decode(s + "=" * (4 - (len(s) % 4)))

pyproject.toml

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+[project]
+name = "b64url"
+version = "1.0.0"
+description = "URL-safe Base64 encoding and decoding without padding, encoding bytes into str, avoiding base64 module's flaws."
+readme = "README.md"
+requires-python = ">=3.8"
+dependencies = []
+authors = [
+    {name = "Leo Vasanko"},
+]
+keywords = ["base64", "base64url", "urlsafe_b64encode", "urlsafe_b64decode"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "License :: Public Domain",
+    "Programming Language :: Python :: 3",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+    "Topic :: Utilities",
+]
+
+[project.urls]
+Homepage = "https://github.com/LeoVasanko/b64url-python"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[tool.hatch.build.targets.wheel]
+packages = ["b64url.py"]