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jcs

JCS - JSON Canonicalization

jcs v0.2.1 1.5M downloads/30d#3,855 on PyPI5
Permissive license Apache-2.0 Abandoned released

What it is and what it does

JCS is a Python 3 implementation of RFC 8785 JSON canonicalization. It transforms JSON objects into a canonical form—a deterministic byte sequence that represents the same data structure identically every time, regardless of key order or whitespace. This is essential when you need to hash JSON data, verify digital signatures, or compare JSON structures byte-for-byte.

The package has no runtime dependencies and installs cleanly. It supports Python 3.6.2 and later. However, it has been abandoned since April 2022 with no active maintenance, so while the core algorithm is stable, you should verify that the implementation meets your security and compatibility requirements before relying on it in production.

Use it for:

  • Hashing JSON payloads to detect tampering or verify integrity in APIs and data pipelines.
  • Creating deterministic signatures for JSON documents in blockchain or cryptographic applications.
  • Comparing JSON structures for equality without being affected by formatting or key ordering.
  • Normalizing JSON before storing it in a content-addressable system or deduplication cache.
  • Implementing RFC 8785 compliance in systems that require standards-based JSON canonicalization.

Worth the install?

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

Canonicalizes JSON according to RFC 8785, producing a deterministic byte representation suitable for hashing and digital signatures.

Yes, if you need RFC 8785 compliant JSON canonicalization and can accept an abandoned package. The implementation is simple and has no dependencies, making it low-risk to integrate. However, verify that the algorithm meets your security requirements and test thoroughly, since there will be no upstream fixes for any future issues you discover.

Install

jcs on PyPI

pip

pip install jcs

uv

uv add jcs

poetry

poetry add jcs

Installing jcs

Before you install

Low friction installation with no runtime dependencies. However, the package is abandoned—last release was 2022-04-10 and no commits since then. Use only if the RFC 8785 implementation is stable enough for your needs and you can maintain it yourself if issues arise.

License in practice

Licensed under Apache-2.0 (permissive). You may use, modify, and distribute it freely in commercial and private projects, provided you include the license notice.

Quickstart

pip install jcs

import jcs
data = jcs.canonicalize({"tag": 4})

Verify before relying

  • Whether the RFC 8785 implementation handles all edge cases correctly for production use cases.
  • Whether abandonment affects compatibility with modern Python versions beyond those listed (3.7–3.10).

Package facts

License Apache-2.0 (permissive)
Python support supports the current Python release (>=3.6.2)
Install friction low — pure-Python wheel
Runtime dependencies none
Maintenance abandoned — 1,587 days since the last release
Last repo commit
First released
Downloads 1,479,172/month — #3,855 on PyPI (30-day window, as of 2026-08-14)
Known vulnerabilities none known (OSV.dev, checked 2026-08-14)

Evidence: jcs-0.2.1-py3-none-any.whl

Keywords: jcs, json, canonicalization, deterministic, serialization, hash

License :: OSI Approved :: Apache Software LicenseProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9

Tags

json canonicalizationdeterministic json serializationrfc 8785 jsonjson hashingcanonical json formatjson signature verificationdeterministic json encoding
json-serializationcryptographydeterministic-hashing

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