---
id: mscerts
version: "2026.7.1"
license: MPL-2.0
license_treatment: copyleft
maintenance: active
---

# mscerts — Python package for providing Microsoft's CA Bundle.

License: copyleft · Maintenance: active · Downloads: 171.5K/mo

## What it is and what it does

mscerts is a Python package that bundles Microsoft's Root Certificate Authorities from the Microsoft Trusted Root Program, similar to how certifi packages Mozilla's certificates. It provides a single function, `where()`, that returns the file path to a PEM-formatted certificate bundle, and can also be invoked from the command line. The package has no runtime dependencies and supports Python 3.7 through 3.14.

The package is explicitly positioned as a specialized alternative to certifi for scenarios where Microsoft's certificate store is specifically required—notably in projects like signify that validate Windows signatures. The maintainers warn that Microsoft's CA program allows granular deprecation of individual CAs that certificate bundle files cannot represent, meaning the bundle may inadvertently trust certificates no longer trusted in their intended context. For most general-purpose use, certifi is recommended instead.

Use it for:

- Validate Windows code signatures or Authenticode certificates in Python applications that need Microsoft's trust store.
- Build tools or security software that must respect Microsoft's specific CA trust decisions rather than Mozilla's.
- Environments where only Microsoft-trusted CAs are acceptable for compliance or policy reasons.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides access to Microsoft's Root Certificate Authorities bundle for Python, allowing applications to reference the Microsoft Trusted Root Program's CA certificates.

Yes, but only if you specifically need Microsoft's CA bundle. For general HTTPS and certificate validation, use certifi instead. Install mscerts only when your application explicitly requires Microsoft's Root Certificate Authorities—such as validating Windows signatures or in compliance-constrained environments. Be aware of the deprecation limitation documented in the package description.

## Install

pip install mscerts
uv add mscerts
poetry add mscerts

## Installing mscerts

Before you install: Low installation friction with no runtime dependencies. Active maintenance as of July 2026, though the project has modest visibility (5 stars). The package is a straightforward certificate bundle mirror.

License in practice: Licensed under MPL-2.0 (copyleft). Users must comply with Mozilla Public License 2.0 terms if they modify or redistribute the package; for typical use (reading certificates), the license poses minimal practical constraint.

Quickstart:

pip install mscerts

import mscerts
print(mscerts.where())

Verify before relying:

- Whether the Microsoft CA deprecation warning (granular CA removal not reflected in bundle files) affects your specific use case or certificate validation chain.
- Current size and update frequency of the Microsoft certificate bundle relative to your security requirements.

## Package facts

- License: MPL-2.0 (copyleft)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 171.5K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

microsoft root certificates, microsoft ca bundle python, mscerts certificate authority, windows trusted root certificates, microsoft certificate store access, certificate-authority, windows-security

[View on SkillFed](https://skillfed.io/packages/mscerts) · [View on PyPI](https://pypi.org/project/mscerts/)