---
id: reedsolo
version: "1.7.0"
license: Public Domain
license_treatment: permissive
maintenance: active
---

# reedsolo — Pure-Python Reed Solomon encoder/decoder

License: permissive · Maintenance: active · Downloads: 2.8M/mo

## What it is and what it does

Reedsolo is a Reed-Solomon error-correction codec that protects data from corruption by adding redundancy symbols. It works with bytes and burst-type errors (common in storage media like hard drives) rather than bit-level noise. The library offers both a pure-Python implementation and an optional Cython-accelerated version for performance-critical use.

You initialize a codec with a number of error-correction symbols, then encode data by appending those symbols, and decode by passing potentially corrupted data back to recover the original. The codec can correct up to half as many errors as you have correction symbols, or twice as many erasures if you know which positions are corrupted. It's designed for data-at-rest scenarios (backup, archival, storage) rather than streaming or network transmission.

Use it for:

- Protect archived files from bitrot by encoding with Reed-Solomon and storing the result on unreliable media
- Add redundancy to backup data so that a few corrupted sectors can be automatically repaired
- Implement erasure coding for distributed storage where some replicas may be lost or damaged
- Verify data integrity without decoding by using the check() method on received or stored messages
- Correct errors in QR codes or other burst-error-prone encoded data formats

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Encodes and decodes data using Reed-Solomon error correction to detect and repair burst errors, supporting both pure Python and optional Cython-optimized implementations.

Yes. Reedsolo is mature, actively maintained, has no dependencies, and is permissively licensed. Install it if you need to protect stored or transmitted data from burst errors and want a straightforward, well-tested implementation. The pure-Python version is fast enough for most use cases; the optional Cython build is available if you need more speed.

## Install

pip install reedsolo
uv add reedsolo
poetry add reedsolo

## Installing reedsolo

Before you install: Low friction: pure-Python wheel with no runtime dependencies. Maintenance is active with recent commits; the library is mature (Development Status 6) and has been stable since its 2012 release.

License in practice: Public Domain license with permissive treatment; you may use, modify, and distribute freely without attribution requirements.

Quickstart:

pip install reedsolo

from reedsolo import RSCodec
rsc = RSCodec(10)  # 10 error correction symbols
encoded = rsc.encode(b'hello world')
decoded_msg, _, _ = rsc.decode(encoded)
print(decoded_msg)

Verify before relying:

- Whether the optional Cython build significantly improves performance for typical workloads
- Maximum practical message length before performance degrades
- Real-world bitrot detection rates compared to checksums or hashing

## Package facts

- License: Public Domain (permissive)
- Python support: unspecified
- Install friction: low
- Maintenance: active
- Downloads: 2.8M/month (top 5,000 on PyPI)
- Known vulnerabilities: none known

## Tags

reed solomon error correction, data recovery from corruption, burst error correction, bitrot protection, erasure coding library, error detection and repair, galois field codec, error-correction, data-integrity, storage-protection

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