How to Install hypothesis in Python

v6.151.12 Testing & QA Python >=3.10

The property-based testing library for Python

Install pip install hypothesis

What is hypothesis?

The property-based testing library for Python

Hypothesis is the property-based testing library for Python. With Hypothesis, you write tests which should pass for all inputs in whatever range you describe, and let Hypothesis randomly choose which of those inputs to check - including edge cases you might not have thought about. For example:

This randomized testing can catch bugs and edge cases that you didn't think of and wouldn't have found. In addition, when Hypothesis does find a bug, it doesn't just report any failing example — it reports the simplest possible one. This makes property-based tests a powerful tool for debugging, as well as testing.

fails with the simplest possible failing example:

PyPI page → Author: "David R. MacIver and Zac Hatfield-Dodds" <david@drmaciver.com>

Quick Start

Minimal example to get started with hypothesis:

import hypothesis

print(hypothesis.__version__)

Installation

pip (standard)

pip install hypothesis

Virtual environment (recommended)

python -m venv venv
source venv/bin/activate   # Windows: venv\Scripts\activate
pip install hypothesis

pip3

pip3 install hypothesis

conda

conda install -c conda-forge hypothesis

Poetry

poetry add hypothesis

Dependencies

Installing hypothesis will also install these packages:

exceptiongroup sortedcontainers

Verify the Installation

After installing, confirm the package is available:

python -c "import hypothesis; print(hypothesis.__version__)"

If this prints a version number, installation succeeded. If you see a ModuleNotFoundError, see the errors section below.

Installation Errors

Common errors when installing hypothesis with pip.

ModuleNotFoundError: No module named 'hypothesis'

Cause: The package is not installed in the current Python environment.

Fix: Run pip install hypothesis. If using a virtual environment, ensure it is activated first.

ModuleNotFoundError: No module named 'hypothesis' (installed but still failing)

Cause: pip installed the package into a different Python than the one running your script.

Fix: Use python -m pip install hypothesis to install into the interpreter you are running.

ImportError: cannot import name 'X' from 'hypothesis'

Cause: The function or class does not exist in the installed version.

Fix: Check the version with pip show hypothesis and upgrade with pip install --upgrade hypothesis.

pip: command not found

Cause: pip is not in PATH or Python was not added to PATH during installation.

Fix: Try python -m pip install hypothesis. On macOS/Linux try pip3.

PermissionError: [Errno 13] Permission denied

Cause: No write access to the system Python package directory.

Fix: Use a virtual environment, or add --user: pip install --user hypothesis

SSL: CERTIFICATE_VERIFY_FAILED

Cause: pip cannot verify PyPI's SSL certificate — common behind corporate proxies.

Fix: Try: pip install --trusted-host pypi.org --trusted-host files.pythonhosted.org hypothesis

Recent Releases

VersionReleased
6.151.12 latest 2026-04-08
6.151.11 2026-04-05
6.151.10 2026-03-29
6.151.7 2026-02-16
6.151.8 2026-02-16

Full release history on PyPI →

Manage hypothesis

Upgrade to latest version

pip install --upgrade hypothesis

Install a specific version

pip install hypothesis==6.151.12

Uninstall

pip uninstall hypothesis

Check what is installed

pip show hypothesis

Last updated: 2026-04-11 • Data from PyPI