Plotly.js vs plotly.py
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
Open source · MIT
A JavaScript library for drawing interactive charts in web pages, also the engine behind Plotly in Python and
Open source · MIT
A Python library for making interactive, browser-based charts and graphs.
The short answer
Choose Plotly.js if you need…
- Web developers who want interactive charts in their own site or app
- Data analysts who already use Python or R Plotly and want to understand the JavaScript side
- Teams building dashboards that need 3D or scientific chart types
- People comfortable with basic HTML and JSON who want charts without much code
Choose plotly.py if you need…
- Python users who want hoverable, zoomable charts without writing JavaScript
- Data analysts working in Jupyter notebooks
- People building shareable HTML charts for reports
- Developers embedding charts in Dash dashboards
Side-by-side
| Plotly.js | plotly.py | |
|---|---|---|
| Type | Library | Library |
| Price | Free and open source | Free and open source |
| Licence | MIT | MIT |
| GitHub stars | 18.4k | 18.9k |
| Setup difficulty | Beginner | Beginner |
| How you get it | Install with a package manager | Install with a package manager |
| Main language | JavaScript | Python |
| Last code update | 7 days ago | 5 days ago |
What each one is
Plotly.js
Plotly.js is a JavaScript library that draws interactive data visualizations such as statistical charts, 3D graphs, scientific charts, map charts and financial charts. You describe your data and layout as a JSON-like object, and the library renders the chart in a web page. The same library also powers the Python and R packages named plotly.
plotly.py
plotly.py is a Python library for creating interactive charts that open in a web browser. It is built on top of plotly.js and lets you describe a chart in code, then view it in Jupyter notebooks, as standalone HTML files, or inside Dash applications. The README says plotly.js provides over 30 chart types, including 3D, statistical, map and financial charts.
Best for
Plotly.js
- Web developers who want interactive charts in their own site or app
- Data analysts who already use Python or R Plotly and want to understand the JavaScript side
- Teams building dashboards that need 3D or scientific chart types
- People comfortable with basic HTML and JSON who want charts without much code
plotly.py
- Python users who want hoverable, zoomable charts without writing JavaScript
- Data analysts working in Jupyter notebooks
- People building shareable HTML charts for reports
- Developers embedding charts in Dash dashboards
Strengths
Plotly.js
- Supports dozens of chart types, including 3D, scientific, map and financial charts
- Can be used with no build step by loading it from a CDN, or installed through npm
- Actively maintained by Plotly, with an MIT license
plotly.py
- Charts are interactive by default, so users can hover, zoom and inspect data
- Two APIs: a short high-level one (Plotly Express) and a detailed one (Graph Objects)
- Licensed under MIT with a large community and active maintenance
Not ideal for
Plotly.js
- Users who only need a simple static chart image; a lighter charting library may be enough
- Projects with strict bundle size limits unless they choose a custom or partial bundle, since the full build is large
- Anyone needing WebGL 2 features, since the README only mentions a WebGL 1 workaround for multiple graphs
plotly.py
- People who only need static images for print; the README points to a separate Kaleido package and a Chrome install for that, which adds setup
- Users who need a non-Python language; this project is Python-specific
- Projects needing a built-in dashboard server on its own, since the README links Dash as a separate product
Trade-offs
Plotly.js
- The full bundle is large, so you may need to build a custom bundle to keep pages light
- Advanced setup such as custom builds or bundling requires reading additional guides
- Some features like MathJax rendering need separate loading and extra configuration
plotly.py
- Static image export needs an extra package and a Chrome or Chromium install
- Interactive charts depend on a browser, so they are less suited to fully offline or print-only workflows
- The README is truncated here, so detailed API coverage and version-specific changes were not verified
Getting started
Plotly.js
Install the ready-to-use distributed bundle
npm i --save plotly.js-dist-minplotly.py
Install plotly with pip
pip install plotlyInstall with Plotly Express support
pip install plotly[express]Frequently asked questions
What is the difference between Plotly.js and plotly.py?
Plotly.js: A JavaScript library for drawing interactive charts in web pages, also the engine behind Plotly in Python and . plotly.py: A Python library for making interactive, browser-based charts and graphs. Plotly.js suits web developers who want interactive charts in their own site or app, while plotly.py suits python users who want hoverable, zoomable charts without writing javascript.
Are Plotly.js and plotly.py free?
Plotly.js: Free and open source. plotly.py: Free and open source.
Is Plotly.js or plotly.py more popular?
plotly.py has more GitHub stars (18.9k) than Plotly.js (18.4k). Popularity isn't the same as fit — check which one matches your use case above.
What are other alternatives to Plotly.js and plotly.py?
Other options people compare them with include Chart.js, visx, deck.gl, Recharts, uPlot.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.