Altair is a declarative data visualization library for Python that generates Vega-Lite specifications. It functions as a tool for mapping data to graphical marks using a high-level syntax, allowing users to describe the desired visual outcome instead of writing imperative drawing commands.
The framework enables the creation of interactive charts and graphics, including linked views and filtered displays that respond to user input in real time. It supports the design of multi-view dashboards by combining visualizations into layered or faceted layouts.
The library provides capabilities for statistical graphics production, data transformation for analysis, and the ability to export visualizations to various image and web formats. It renders natively within notebooks and integrated development environments to support iterative data analysis.