Projects using Hypothesis

Hypothesis is downloaded over 4 million times each week, and was used by more than 5% of Python users surveyed by the PSF in 2023!

The following notable open-source projects use Hypothesis to test their code: pytorch, jax, PyPy, numpy, pandas, attrs, chardet, bidict, xarray, array-api-tests, pandera, ivy, zenml, mercurial, qutebrowser, dry-python/returns, argon2_cffi, axelrod, hyper-h2, MDAnalysis, napari, natsort, vdirsyncer, and pyrsistent. You can find thousands more projects tested by Hypothesis on GitHub.

There are also dozens of first-party and third-party extensions integrating Hypothesis with a wide variety of libraries and data formats.

Research papers about Hypothesis

Looking to read more about Hypothesis and property-based testing? Hypothesis has been the subject of a number of research papers:

1. Hypothesis: A new approach to property-based testing (2019)*

2. Test-Case Reduction via Test-Case Generation: Insights from the Hypothesis Reducer (2020)*

3. Deriving semantics-aware fuzzers from web API schemas (2022)*

4. Tyche: Making Sense of PBT Effectiveness (2024)*

5. An Empirical Evaluation of Property-Based Testing in Python (2025)

6. Agentic Property-Based Testing: Finding Bugs Across the Python Ecosystem (2025)*

* Author list includes one or more Hypothesis maintainers