plotglass.com

What It Is

PlotGlass is a JavaScript charting library for real-time data plotting in the browser. Its core focus is “rendering a large number of charts on a single page at a reasonable frame rate.” It deliberately uses WebGL as its rendering foundation to avoid the extra overhead that SVG or Canvas can introduce in high-volume, high-refresh-rate scenarios.

Core Capabilities

Based on the project description, PlotGlass is not positioned as a general-purpose commercial charting library, but rather as a high-performance time-series plotting tool. A key design highlight is that it uses a single WebGL context across the entire page to render all charts, avoiding browser limits on the number of WebGL contexts and reducing the overhead of managing multiple contexts. The rough performance target stated by the project is: on a 2017 MacBook Air, a browser window should be able to render 100 charts, each containing one 100k-point time series, updating at least at 15Hz while keeping page scrolling and interactions smooth.

Development and Documentation

The project provides a GitHub link, accepts Pull Requests, and can be built locally with webpack to generate plotGlass.js, along with JSDoc documentation. Tests can be run with npm run test. For the local WebSocket example, run node examples/timeSeriesServer.js and then open examples/timeSeries.html. The documentation entry point and JSDoc are developer-friendly, but the description also makes clear that the project is still a proof of concept: the API is still changing, and future versions may introduce breaking changes.

Pricing and Open Source

The description does not mention commercial pricing, paid editions, or hosted service options. Since the project is available on GitHub and accepts contributions, it appears to follow an open-source project model, but the license is not stated in the text. Companies should therefore verify the licensing terms before adoption.

Pros and Cons

Its strengths are a clear performance goal and suitability for large volumes of real-time TimeSeries data. The single-WebGL-context architecture is valuable for complex dashboards. The drawbacks are also obvious: it currently only demonstrates TimeSeries plots and only provides a JSON WebSocket data example. The project is still immature, the API is unstable, and information about ecosystem integrations is lacking.

Who It’s For and Access from China

PlotGlass is better suited to frontend visualization engineers, monitoring dashboard developers, or teams exploring high-performance real-time charting. It is less suitable as a stable, ready-to-use general-purpose BI charting library. The source text does not provide information about access from China; if GitHub access is unstable, obtaining the source code and documentation may be affected. Alternatives to consider include ECharts, uPlot, Plotly.js, Highcharts, and D3.js.