base64-rs

High-performance base64 encoder/decoder written in Rust🦅

Features

• High-performance base64 encoder/decoder

• Runtime SIMD dispatch with support for:

  • AVX-512F, AVX-512VL, AVX-512VBMI, AVX2, AVX
  • SSE4.2, SSE4.1, SSSE3
  • NEON64, NEON32

• Drop-in replacement for CPython base64 (see: below)

Installation

Using pip:

pip install base64-rs

Using uv:

uv pip install base64-rs

Using poetry:

poetry add base64-rs

Examples

import base64_rs

print(base64_rs.b64encode(b"lava-sh")) # b'bGF2YS1zaA=='

Compatibility with CPython base64

base64-rs is a drop-in replacement for CPython's base64 lin on Python 3.15+. Its compatible functions use the same call signatures, parameters, defaults, and return values, so existing imports can be replaced without changing call sites.

import base64_rs as base64

print(base64.b64encode(b"lava-sh"))           # b'bGF2YS1zaA=='
print(base64.standard_b64encode(b"\xfb\xff")) # b'+/8='
print(base64.urlsafe_b64encode(b"\xfb\xff"))  # b'-_8='

References

Papers

• 📗 Base64 encoding and decoding at almost the speed of a memory copy
• 📗 AVX512F base64 coding and decoding
• 📗 Base64 encoding & decoding using AVX512BW instructions
• 📗 Base64 encoding with SIMD instructions
• 📗 Base64 decoding with SIMD instructions

GitHub repos

• 🐙 WojciechMula/base64simd
• 🐙 WojciechMula/base64-avx512
• 🐙 aklomp/base64
• 🐙 Nugine/simd
• 🐙 BLAKE3-team/BLAKE3
• 🐙 simdutf/simdutf

Contributors