Plotly

Plotly creates interactive (zoomable, hoverable) charts in the browser. v6.0 (2025) drops big dependencies (Pandas is optional) and improves performance.

When to Use

• Dashboards: Streamlit, Dash.
• 3D Plots: Rotating 3D scatter plots.
• Interactivity: Users need to drill down into data.

Core Concepts

Plotly Express (px)

High-level API. px.scatter(df, x="a", y="b", color="c").

Graph Objects (go)

Low-level API. go.Figure(data=[go.Scatter(...)]).

Dash

The framework for building web apps with Plotly charts.

Best Practices (2025)

Do:

• Use Plotly Express: It covers 90% of use cases.
• Use WebGL: render_mode='webgl' for large datasets (>10k points).

Don't:

• Don't use it for static papers: Use Matplotlib for print.

References

• Plotly Python