Matplotlib
What it is: Python's foundational plotting library. Every other Python viz library builds on it.
What It Does Best
Publication quality. Control every pixel. Used in academic papers, journals, scientific publications.
Infinitely flexible. If you can imagine it, you can build it. No chart type is off-limits.
Static, perfect exports. PNG, PDF, SVG at exact dimensions you specify.
Pricing
Free. Open source, BSD license.
When to Use It
✅ Need publication-quality static images
✅ Precise control over every element
✅ Scientific or academic visualization
✅ Custom chart types not available elsewhere
When NOT to Use It
❌ Need quick, exploratory plots (Seaborn faster)
❌ Want interactive charts (Plotly better)
❌ Beginners who want simple syntax (steep learning curve)
Bottom line: The Swiss Army knife of Python plotting. Verbose, powerful, and essential. Learn this if you're serious about data visualization in Python.