contextvars

What it is and what it does

This package backports Python 3.7's contextvars module to Python 3.6, implementing PEP 567 context-local state. It allows you to create and manage context variables that maintain separate values across concurrent execution contexts—useful in async code and thread pools where thread-local storage is insufficient.

The package is now largely obsolete: Python 3.7+ includes contextvars in the standard library, and the package itself has been abandoned since its last release on 2019-04-01 with no active maintenance. It exists primarily as a compatibility shim for legacy Python 3.6 codebases. The standard library always takes precedence, so listing it as a dependency is safe but unnecessary for modern projects.

Use it for:

• Maintaining request-scoped state in async frameworks running on Python 3.6.
• Passing context through concurrent.futures thread pools without global variables.
• Porting code that uses contextvars from Python 3.7+ down to Python 3.6 environments.

Worth the install?

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

Provides the PEP 567 contextvars module for Python 3.6, enabling context-local state management in concurrent code.

No. If you are on Python 3.7 or later, use the standard library contextvars. If you must support Python 3.6, this backport is your only option, but the lack of maintenance since 2019-04-01 and high install friction make it a last resort. Modern projects should not depend on this.

Install

contextvars on PyPI

pip install contextvars

uv add contextvars

poetry add contextvars

Installing contextvars

Before you install

High install friction due to source distribution. Package is abandoned as of 2019 with no maintenance since its last release. Modern Python versions include contextvars in the standard library, making this backport obsolete for most use cases.

License in practice

Licensed under Apache License, Version 2.0 (permissive). No restrictions on commercial or private use; attribution required.

Quickstart

pip install contextvars

import contextvars

my_var = contextvars.ContextVar('my_var')
my_var.set('value')

Python 3.6 only; Python 3.7+ includes contextvars in the standard library and will use that instead of this backport.

Verify before relying

• Whether asyncio event loop support was ever added after the 2019 release note stating it was not yet available.
• Compatibility with Python 3.5 (listed in classifiers) despite the description stating Python 3.6 support.
• Current status of Python 3.6 support lifecycle and whether this backport remains usable.

Package facts

Evidence: contextvars-2.4.tar.gz

Tags

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