Dyalog APL Development Operations. Used by the Carlisle Group for project and dependency management, releasing new versions, etc.
HTML generation, and Markdown to HTML conversion. Go from DOM to HTML and back. HTMLRenderer framework for cross-platform desktop UI. Used by this site to convert Markdown to HTML.
A Web server.
Read Excel files in .xlsx format (XML) into APL.
A test framework.
Convert time strings to time numbers.
Charts and graphs.