Snyk for Python
Snyk provides security scanning on projects for vulnerabilities through our CLI and the application UI (
The following describes how to use Snyk to scan Python projects:


Features might not be available, depending on your subscription plan.
Package managers / Features
CLI support
Git support
License scanning
PyPI licenses are supported for all Python projects.

How it works

Once we’ve built the tree, we can use our vulnerability database to find vulnerabilities in any of the packages anywhere in the dependency tree.
To scan your dependencies, you must ensure you have first installed the relevant package manager, and that your project contains the supported manifest files.
The way by which Snyk analyzes and builds the tree varies depending on the language and package manager of the project, as well as the location of your project.

Snyk CLI tool for Python projects

The way by which Snyk analyzes and builds the tree varies depending on the language and package manager of the project.


Snyk requires the full, nested dependency tree in order to run tests. Requirements.txt files only contain the top-level dependencies and not the nested or transitive dependencies. The most efficient way to ensure accuracy is to install the full pip project.
Snyk runs tests against the specific pip installation used for that specific service/product rather than an unlinked, separate dependency tree.
In order to scan the full dependency tree, Snyk analyzes the installed packages to ensure none are missing. This happens even when not explicitly specified in the manifest file.


In order to build the dependency tree, run pipenv install as Snyk needs this to create the pipenv graph which is then used for the dependency scan to fulfil itself.
Snyk uses the built dependency tree to analyze the Pipfile.

In order to build the dependency tree, Snyk analyzes the file, and detects packages listed in the install_requires key.
There is no auto-discovery for this file, it must be specified manually:
snyk test
You can convert to requirements.txt by installing the packages into a virtual environment and then running pip freeze.


To find issues in a Python Poetry application Snyk uses pyproject.toml and poetry.lock files. Note both these files must be present for Snyk to identify Poetry dependencies and test for issues.

Additional support details


CLI parameters for Python


  • Ensure you've installed the relevant package manager before you begin using the Snyk CLI tool.
  • Ensure you've included the relevant manifest files supported by Snyk before testing.
  • Install and authenticate the Snyk CLI to start analyzing projects from your local environment. Read more about our CLI in Getting started with the CLI as well.


When scanning your Python project for vulnerabilities, use these options to modify commands:
Snyk uses Python in order to scan and find your dependencies. Snyk needs the Python version to start scanning, and defaults to "python"
If you are using multiple Python versions, use this parameter to specify the correct Python command for execution.
For example: snyk test --command=python3
See Using different Python versions for more details
Skip packages when they can’t be found in the environment (for example, private packages that can’t be accessed from the machine running the scan).
Specify a specific file to test. By default, Snyk scans the requirements.txt file on the top level of the project.
If explicitly specified with this parameter, Snyk can recognize any manifest files named *req*.txt, where: Each (*) is a wildcard and req can appear anywhere in the file name.
For example, Snyk recognizes your manifest file when you have renamed it to requirements-dev.txt.
Note: --package-manager=pip should be added to your cmd if the file name is not requirements.txt
This parameter is mandatory if you specify a value for the --file parameter that is not to a requirements.txt file. The test fails without this parameter. Specify this parameter with the value pip.

Git services for Python projects

Python projects can be imported from any of the Git repositories we support.
In order to test your Python projects using pip as a package manager, we analyze your requirements.txt file, and so you must have this file in your repository before importing.
If you’ve renamed your requirements.txt files (for example, if you have renamed a file to requirements-dev.txt), we try to import every file that follows the **/*req*.txt convention as a Python project.
If you've placed your files in a requirements folder (for example, if you have placed your file under requirements/requirements.txt) we try to import every file that follows the **/requirements/*.txtconvention as a Python project.
If you are using a package manager that creates different manifest file formats other than requirements.txt, then either convert or import (depending on the package manager/supported files) the manifest file to the requirements.txt format.
For example:
dephell deps convert --from=conda --to=requirements.txt

Using different Python versions

Some Python projects may have dependencies that are only valid using Python 3. By default, Snyk scans with Python 2.
You can adjust the version of Python Snyk uses to scan dependencies, in both the CLI and Git integration.

Setting Python version in the CLI

Add the following parameter to snyk test or snyk monitor
You can also set a specific Python version by adding the following to a .snyk policy file.
python: '3.7.2'

Setting Python version in Git projects

When testing projects imported from Git, Snyk uses a recent version of either Python 2 or Python 3, for example 2.7.4 or 3.7.4.
By default Snyk tests using Python 2.
To define which Python major version Snyk uses to test your Git imported projects, use either organization settings, or a .snyk policy file.
To define Python version for all projects in an organization:
  1. 1.
    Log in to your account and navigate to the relevant group and organization to manage.
  2. 2.
    Click on settings
    > Languages.
  3. 3.
    Click Edit settings for Python.
  4. 4.
    Select to use Python 2 or Python 3 when testing projects for this organization
We recommend you create different organizations to work with different Python versions.
If you prefer to use one organization but require projects to use different Python versions, you may add a .snyk file to a project repository, and specify the desired version.
The.snyk file must be in the same directory as the project manifest file.

Major and minor versions

On finding a .snyk file, Snyk detects the major version specified, and uses this to control whether the project is tested with Python 2 or Python 3. It does not use the exact version specified.
For example, for projects imported via Git:
python: '3.7.2'
This example tells Snyk to use a recent version of Python 3, but Snyk will not use the exact minor and patch version specified.
Last modified 1mo ago