Is igraph Open Source and Free to Use?

Updated

Yes. The igraph website describes igraph as “open source and free,” and the project publishes its source code and releases on GitHub. That statement covers the igraph project as a whole; the individual language packages (R, Python, Mathematica, C/C++) are separate distributions, and their own license terms should be checked on each package's page or repository before redistribution or commercial embedding.

What “open source and free” means here

The homepage positions igraph as “a collection of network analysis tools with the emphasis on efficiency, portability and ease of use,” and explicitly states it is open source and free. The practical implications:

  • Source access: releases are distributed from the GitHub releases page, so you can read, modify, and build the code yourself.
  • No cost to use: the project does not present igraph as a paid product; there is no pricing or subscription information on the site.
  • Multiple entry points: you can use igraph from R, Python, Mathematica, and C/C++, plus the IGraph/M package for Mathematica.

The site does not publish a single unified license statement for all bindings on the page reviewed. If licensing matters for your use case (for example, shipping igraph inside a commercial product), confirm the license of the specific package you install rather than relying on the general “open source” description.

Available packages and where to get them

Package Language / environment Where it lives
igraph R package R Linked from igraph.org; also on CRAN
python-igraph Python Linked from igraph.org; also on PyPI
IGraph/M Mathematica Linked from igraph.org
igraph C library C/C++ GitHub releases page

The site also lists an igraphdata R package for datasets and a “Community packages” section for third-party extensions.

Version status you should know before installing

The project reached a milestone with C/igraph 1.0.0 (September 20, 2025), described as arriving “nearly twenty years after the first igraph release.” The 1.0 series focuses on “a stable and more consistent interface” and introduces an official versioning policy (VERSIONING.md). A bugfix release, C/igraph 1.0.1, followed on December 26, 2025.

The last planned 0.x release was C/igraph 0.10.17 (September 19, 2025). The project notes that 1.0 includes “quite a few breaking changes” relative to 0.x, so existing code written against 0.10 may need adjustment.

Language bindings have their own release cadence — the news list shows, for example, python-igraph 0.11.8 and 0.11.6, and notes that “The igraph R package crossed the 2.0 threshold!” Check the binding's own release notes rather than assuming the C library version number applies.

How to verify the current state yourself

  1. Go to igraph.org and use the “Packages” links to reach the R, Python, Mathematica, and C library pages.
  2. For source and changelogs, follow the GitHub releases page referenced in each release announcement.
  3. For licensing details on a specific binding, open that package's repository or its CRAN/PyPI listing, where the license field is stated.
  4. For usage questions, the site points to a Forum and Discord, plus a Code of Conduct for community participation.

If your question is simply “can I try igraph without paying,” the answer from the official site is yes — it is described as open source and free, and the code is publicly available on GitHub.