## What is Perspective?

Perspective is an interactive analytics and data visualization component, which is especially well-suited for large and/or streaming datasets. Use it to create user-configurable reports, dashboards, notebooks and applications, then deploy stand-alone in the browser, or in concert with Python and/or Jupyterlab.

### Features

A fast, memory efficient streaming query engine, written in C++ and compiled for both WebAssembly and Python, with read/write/streaming for Apache Arrow, and a high-performance columnar expression language based on ExprTK.

A framework-agnostic User Interface packaged as a Custom Element, powered either in-browser via WebAssembly or virtually via WebSocket server (Python/Node).

A JupyterLab widget and Python client library, for interactive data analysis in a notebook, as well as scalable production Voila applications.

## JavaScript

Interactive dashboards built on Perspective.js Custom Elements are easy to integrate into any web application framework.

Using Perspective's simple query language, elements like `<perspective-viewer>` can be symmetrically configured via API or User interaction. Web Applications built with Perspective Custom Elements can be re-hydrated from their serialized state, driven from external Events, or persisted to any store. Workspaces can mix virtual, server-side Python data with in-browser client data seamlessly, and independent data Views can be cross-filtered, duplicated, exported, stacked and saved.

To achieve Desktop-like performance in the Browser, Perspective.js relies on WebAssembly for excellent query calculation time, and Apache Arrow for its conservative memory footprint and efficient data serialization.

## Python

`perspective-python`, built on the same C++ data engine used by the WebAssembly version, implements the Perspective API directly in Python, either as a virtualized server for Production, or as an embedded JupyterLab Widget for Research.

For Application Developers, virtualized `<perspective-viewer>` will only consume the data necessary to render the current screen, enabling ludicrous size datasets with nearly instant load. Or - efficiently stream the entire dataset to the WebAssembly runtime via Apache Arrow, and give your server a break!

For Researchers and Data Scientists, `PerspectiveWidget` is available as a Jupyter/JupyterLab widget, allowing interactive Pandas and Apache Arrow visualization within a notebook.