---
id: pymzml
version: "2.6.1"
license: The MIT license
license_treatment: permissive
maintenance: active
---

# pymzml — high-throughput mzML parsing

License: permissive · Maintenance: active · Downloads: 166.3K/mo

## What it is and what it does

pymzml is a Python parser for mzML, the standard mass spectrometry data format used in proteomics and metabolomics research. It provides fast, seekable access to spectra stored in mzML files—including support for compressed formats—and includes utilities for spectrum comparison and visualization. The core library depends only on numpy and regex, keeping installation simple, though optional extras add plotting and deconvolution capabilities.

The package is aimed at bioinformaticians and researchers who need to programmatically extract and analyze mass spectrometry data. It has been actively maintained since 2012 and currently requires Python 3.10 or higher. Installation is straightforward via pip, with optional feature flags for extended functionality like interactive plotting or pynumpress compression support.

Use it for:

- Extract and iterate over spectra from mzML files in a proteomics workflow.
- Build custom mass spectrometry data analysis pipelines that need rapid spectrum access.
- Compare spectra or perform spectral matching in metabolomics studies.
- Integrate mzML parsing into bioinformatics tools for automated MS data processing.
- Visualize mass spectrometry data interactively during exploratory analysis.

## Worth the install?

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

pymzml parses mzML mass spectrometry data files in Python, providing fast random access to spectra and tools for spectrum comparison and visualization.

Yes. pymzml is actively maintained, has low install friction, carries no known vulnerabilities, and is the standard choice for mzML parsing in Python. Install it if you work with mass spectrometry data in proteomics or metabolomics; the core library is lightweight and optional features are available if needed.

## Install

pip install pymzml
uv add pymzml
poetry add pymzml

## Installing pymzml

Before you install: Low friction install with only numpy and regex as core dependencies. Active maintenance with a recent release (52 days old) and ongoing repository activity. Requires Python 3.10 or higher.

License in practice: MIT license permits commercial and private use with minimal restrictions; you may use, modify, and distribute pymzml provided you include the license notice.

Quickstart:

pip install pymzml
import pymzml
# Parse an mzML file and access spectra
run = pymzml.run.Reader('data.mzML')
for spectrum in run:
    print(spectrum.ID, spectrum.mz, spectrum.i)

Requires Python 3.10 or higher; numpy must be installed before optional dependencies like pynumpress.

Verify before relying:

- Whether the package's spectrum comparison and visualization functions work out-of-the-box or require optional dependencies.
- Performance characteristics for very large mzML files or highly compressed formats.
- Whether random access in compressed files requires specific file preparation or encoding.

## Package facts

- License: The MIT license (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 166.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

mzml parser python, mass spectrometry data parsing, ms data access, spectrum parsing library, proteomics data reader, mzml file reader, mass spec file format, mass-spectrometry, bioinformatics, data-parsing

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