--- id: pronto version: "2.7.3" license: MIT License Copyright (c) 2016-2026 Martin Larralde Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated… (full text in the JSON record) license_treatment: permissive maintenance: aging --- # pronto — Python frontend to ontologies. License: permissive · Maintenance: aging · Downloads: 142.9K/mo ## What it is and what it does Pronto is a Python library that acts as a frontend to ontologies, allowing you to load, manipulate, and export biomedical ontology data. It implements the Open Biomedical Ontologies 1.4 specification and supports three major formats: OBO, OBO Graphs in JSON, and OWL2 in RDF/XML. The library presents ontologies as navigable Python objects—you can access terms by identifier, traverse class hierarchies, create new terms, and serialize back to any supported format. The package depends on chardet, fastobo, networkx, and python-dateutil. It is typed and supports Python 3.7 through 3.14. The library is explicit about non-standard assumptions and missing capabilities, surfacing these as warnings rather than silent failures. Use it for: - Load and query biomedical ontologies to programmatically access term definitions and hierarchies. - Convert OWL2 ontologies to OBO format for downstream tools requiring OBO. - Build or extend ontologies by creating new terms, setting relationships, and exporting. - Iterate over all terms to identify leaf nodes, compute statistics, or validate structure. - Integrate ontology data into bioinformatics pipelines needing structured semantic information. ## Worth the install? AI-flagged interpretation of the facts above — verify before relying. Pronto parses, browses, creates, and exports ontologies in OBO, OBO Graphs JSON, and OWL2 RDF/XML formats, providing a high-level Python interface to biomedical ontology data. Yes. Pronto is a mature, well-maintained library for a specialized but important use case in bioinformatics. Low install friction, no known vulnerabilities, permissive licensing, and broad Python version support make it a low-risk addition. The aging maintenance status is typical for stable libraries. Install it if you need to work with biomedical ontologies in Python. ## Install pip install pronto uv add pronto poetry add pronto ## Installing pronto Before you install: Low install friction with a pure-Python wheel distribution. Maintenance status is aging—last release was 214 days ago—but the repository remains active with recent commits and marked Production/Stable. License in practice: MIT License permits unrestricted use, modification, and distribution with minimal restrictions, suitable for both commercial and open-source projects. Quickstart: from pronto import Ontology go = Ontology("tests/data/go.obo.gz") term = go['CL:0002116'] print(term.name) Verify before relying: - Performance characteristics when working with large ontologies or deeply nested hierarchies. - Completeness of OBO 1.4 format support across the full OBO Foundry catalog. - Stability guarantees for OBO Graphs JSON format, noted as not yet stabilized. ## Package facts - License: MIT License Copyright (c) 2016-2026 Martin Larralde Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated… (full text in the JSON record) (permissive) - Python support: supports_current - Install friction: low - Maintenance: aging - Downloads: 142.9K/month (top 15,000 on PyPI) - Known vulnerabilities: none known ## Tags ontology parser python, OBO format library, biomedical ontology tools, OWL to OBO conversion, ontology graph traversal, bioinformatics, ontology-parsing, semantic-web [View on SkillFed](https://skillfed.io/packages/pronto) · [View on PyPI](https://pypi.org/project/pronto/)