This project makes use of Eagle, provided by Mistachkin Systems.
Eagle: Secure Software Automation

The "/pikchrshow" page:

A pikchr code editor and previewer, allowing users to experiment with pikchr code or prototype it for use in copy/pasting into forum posts, wiki pages, or embedded docs. This version of pikchrshow uses WebAssembly to run entirely in the client browser, without a need for back-and-forth client/server traffic to perform the rendering. The "legacy" version of this application, which sends all input to the server for rendering, can be accessed by adding the "legacy" URL argument.

It optionally accepts a p=pikchr-script-code URL parameter or POST value to pre-populate the editor with that code.