Getting started#


Memray can easily be installed from PyPI.


When installing Memray with pip you need to install it with the Python interpreter you intend to run your profiled application with. In this case example we’re installing it for use with Python 3.9:

python3.9 -m pip install memray

Using the CLI#

You can invoke Memray the following way:

python3.9 -m memray

Or alternatively through the version-qualified memrayX.Y script:


You can also invoke Memray without version-qualifying it:


The downside to the unqualified memray script is that it’s not immediately clear what Python interpreter will be used to execute Memray. If you’re using a virtualenv that’s not a problem because you know exactly what interpreter is in use, but otherwise you need to be careful to ensure that memray is running with the interpreter you meant to use.

Profiling with Memray should be done in two steps:

  1. Run the application to track allocations and deallocations and save the results

  2. Generate the desired report from the captured results

Running the Analysis#

To run memray on the script, use the run subcommand.

memray3.9 run

This will execute the script and track its memory allocations, displaying the name of the file where results are being recorded with a message like:

Writing profile results into

Generating a Flame Graph#

To generate a flame graph displaying memory usage across the application, we can run memray flamegraph and specify the results file:

memray3.9 flamegraph

This will generate the file in the current directory. See the Flame Graph Reporter documentation which explains how to interpret flame graphs.