cobs

What it is and what it does

COBS is a byte-stuffing algorithm that encodes arbitrary binary data into a form containing no zero bytes (0x00), enabling zero bytes to serve as reliable packet delimiters in serial and network protocols. The package provides both basic COBS and COBS/R (a variant that reduces overhead) via Python modules with encode and decode functions. It includes a C extension for performance and a pure Python fallback for portability.

The encoding adds predictable overhead: always 1 byte plus potentially n/254 additional bytes for longer packets. This is more efficient than escape-based methods like PPP, which can double packet size in worst cases. The package accepts any buffer-protocol-compatible input (bytes, bytearray) and returns encoded/decoded bytes; framing (adding or stripping delimiter bytes) is left to the application.

Use it for:

• Implement packet framing in serial communication protocols where zero bytes mark packet boundaries.
• Encode binary data for transmission over channels that cannot safely transmit zero bytes.
• Reduce packet size overhead compared to escape-based byte stuffing in bandwidth-constrained protocols.
• Use COBS/R variant to minimize encoding overhead for small message payloads in embedded systems.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Encodes and decodes data using Consistent Overhead Byte Stuffing (COBS), a method that eliminates zero bytes from encoded packets to enable reliable packet framing in communication protocols.

Yes. COBS is a well-established, stable algorithm with a mature implementation (Production/Stable, MIT license). Install it if you need reliable packet framing in serial/network protocols or must eliminate zero bytes from binary data. Medium install friction is acceptable given the C extension fallback. No known vulnerabilities.

Install

cobs on PyPI

pip install cobs

uv add cobs

poetry add cobs

Installing cobs

Before you install

Medium install friction due to C extension compilation; pure Python fallback available. Package is stable (Production/Stable status) and actively maintained with recent release (2025-07-20), though maintenance cadence is aging.

License in practice

MIT license (permissive) allows unrestricted use, modification, and distribution with minimal restrictions—suitable for both open-source and proprietary projects.

Quickstart

pip install cobs

from cobs import cobs
encoded = cobs.encode(b'Hello world\x00This is a test')
decoded = cobs.decode(encoded)

Requires Python >= 3.6; C extension compilation may fail on some platforms, but pure Python implementation is available as fallback.

Verify before relying

• Performance characteristics of C extension vs. pure Python implementation for typical packet sizes.
• Whether the package handles edge cases like empty input or maximum-length packets as documented.

Package facts

Evidence: cobs-1.2.2-cp312-cp312-win32.whl; cobs-1.2.2-cp312-cp312-win_amd64.whl; cobs-1.2.2-cp313-cp313-win32.whl; cobs-1.2.2-cp313-cp313-win_amd64.whl; cobs-1.2.2-cp314-cp314-win32.whl; cobs-1.2.2-cp314-cp314-win_amd64.whl

Keywords: byte, stuffing

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