pygraphistry

PyGraphistry is the Python client for Graphistry, a GPU-accelerated graph visualization platform. Load a few million nodes and edges, get an interactive zoomable graph in your browser. Free Python library, paid server tiers.

The library is open source and easy to use. Pandas DataFrame in, visualization out. You point it at the Graphistry Hub (free tier with limits) or your own enterprise server. The rendering happens server-side on a GPU, which is what makes this scale to graphs that would melt D3 or sigma.js.

For data scientists doing exploratory analysis on biggish graphs, this is the right tool. The free Hub tier is fine for personal use and demos. Teams that need private data or higher limits pay for the enterprise server, which is real money. Quote-required, not self-serve. If you can't justify that, look at Memgraph Lab, Neo4j Bloom on Aura's free tier, or roll your own with sigma.js.

The catch is the GPU dependency. The client library is free but useless without a Graphistry server, and you can't self-host the server free tier. Plan around that before you build it into a product.