pytest-memray
A simple plugin to use with pytest
Decision gist · record as of 2026-08-14
Yes. The plugin is actively maintained, has low install friction, carries no security vulnerabilities, and solves a real problem—memory profiling in tests—that is otherwise tedious to set up. It's well-suited for projects concerned with memory efficiency or regression detection. The Apache-2.0 license is permissive and poses no barrier to adoption.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.8 or higher; memray itself only runs on Linux and macOS.
- Low friction install with a pure-Python wheel.
- Actively maintained with a release within the past week.
License · maintenance · safety
Apache-2.0 (permissive) — Apache-2.0 permissive license allows use in commercial and private projects with minimal restrictions; you must include a copy of the license.
last release 2026-08-07 (7 days) · last repo commit 2026-08-11 · 422 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 2,893,206 downloads/mo, #2,836 on PyPI
Alternatives
Verify before relying
pip install pytest-memray
pytest --memray tests/
# In a test file:
import pytest
@pytest.mark.limit_memory("100.0KiB")
def test_my_function():
data = [i for i in range(10)]
assert len(data) == 10- Whether the plugin works with pytest fixtures and parametrized tests without additional configuration.
- Performance overhead of native frame tracking and Python allocator tracing modes on large test suites.
- Compatibility with other pytest plugins that also instrument memory or test execution.
What it is and what it does
pytest-memray is a pytest plugin that wraps memray's memory profiling capabilities for test-driven memory debugging. It activates via the `--memray` CLI flag and tracks heap allocations throughout each test, then generates a summary report showing total memory used, allocation counts, and the call stacks responsible for the largest allocations. You can set per-test memory limits using the `limit_memory` marker and fail tests that exceed them; the plugin also supports tracking memory growth across runs with `--fail-on-increase` to catch regressions.
The plugin is designed for developers who need to catch memory leaks or excessive allocations in their test suite without manually instrumenting code. It outputs allocation histograms, identifies the functions and line numbers responsible for the biggest memory consumers, and can optionally show native C-level frames for deeper profiling. Configuration is available both via CLI flags and pytest INI settings.
Use it for
- Catch memory leaks in unit tests by setting per-test memory limits and failing tests that exceed them.
- Identify which functions allocate the most memory during test execution for optimization.
- Track memory usage trends across test runs and fail if a test's memory footprint grows unexpectedly.
- Debug memory issues in CI/CD pipelines by generating detailed allocation reports for each test.
- Profile Python allocator behavior separately from native allocations using `--trace-python-allocators`.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes.
The plugin is actively maintained, has low install friction, carries no security vulnerabilities, and solves a real problem—memory profiling in tests—that is otherwise tedious to set up. It's well-suited for projects concerned with memory efficiency or regression detection. The Apache-2.0 license is permissive and poses no barrier to adoption.
Install
pytest-memray on PyPI
Before you install
Low friction install with a pure-Python wheel. Actively maintained with a release within the past week. Requires only memray and pytest as runtime dependencies, both widely available.
Requires Python 3.8 or higher; memray itself only runs on Linux and macOS.
License in practice
Apache-2.0 permissive license allows use in commercial and private projects with minimal restrictions; you must include a copy of the license.
Quickstart
pip install pytest-memray
pytest --memray tests/
# In a test file:
import pytest
@pytest.mark.limit_memory("100.0KiB")
def test_my_function():
data = [i for i in range(10)]
assert len(data) == 10Verify before relying
- Whether the plugin works with pytest fixtures and parametrized tests without additional configuration.
- Performance overhead of native frame tracking and Python allocator tracing modes on large test suites.
- Compatibility with other pytest plugins that also instrument memory or test execution.
Package facts
| License | Apache-2.0 permissive |
| Python support | Supports the current Python release >=3.8 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | 2 packagesmemraypytest |
| Maintenance | Actively maintained 7 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 2,893,206 / month, #2,836 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Intended Audience :: DevelopersLicense :: OSI Approved :: Apache Software LicenseOperating System :: MacOSOperating System :: POSIX :: LinuxProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.15Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonTopic :: Software Development :: Debuggers |
Evidence: pytest_memray-1.10.0-py3-none-any.whl
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See also pytest-testmon · pystack · pytest-cache · omnimalloc · pyroscope-io · py-spy · pytest-isort · pytest-html · pytest-skip-slow