Ursinus WebIDE

The Ursinus WebIDE is a browser-based integrated development environment developed with Christopher Tralie to provide low-stakes, frequently-assigned coding practice for students across the entire CS curriculum. All code execution runs client-side inside the student’s browser, so the system requires no server infrastructure beyond static web hosting — making it free to operate and freely accessible to anyone on the internet. No software installation is required beyond an off-the-shelf web browser, supporting equity across operating systems and lower-end devices such as Chromebooks.

A demonstration of the system was presented at SIGCSE TS 2026 (55th ACM Technical Symposium on Computer Science Education) in St. Louis, MO. The full demo page is available here:

The Ursinus WebIDE — SIGCSE 2026 Demo

The project is hosted at:

Ursinus WebIDE

Supported Languages

C++, Java, JavaScript, WebGL, Python (Brython and Pyodide), NumPy, R, SQL, Scheme, and Prolog.

Design Goals

The system was designed around a set of educational and operational goals:

• Provide a unified exercise template across all supported languages.
• Run entirely client-side on static pages, eliminating server maintenance costs and scaling problems.
• Remember student net IDs via cookie and support save/load of in-progress code.
• Mirror a tree-based filesystem experience within the browser to scaffold students toward local development workflows.
• Detect and handle infinite loops gracefully rather than freezing the tab.
• Display multimedia assets (images, audio) inline to support multimedia-focused courses.
• Deliver low-stakes automated feedback by detecting common mistakes and surfacing hints in a console-like output panel.
• Persist student work in the browser so students can return to exercises later.
• Connect to learning management systems (LMS) in an encrypted, FERPA-compliant way via Canvas integration.

Student-Facing Features

Preferences

The View menu exposes three persistent preferences stored in localStorage:

Accessibility

Every interactive element carries an aria-label; tab/panel pairs use the ARIA tablist pattern; the ACE editor exposes a screen-reader mode; and all keyboard-driven focus is outlined with a gold :focus-visible ring. The layout is fully responsive, collapsing gracefully below ~900 px for mobile use.

“Explain This Error” Affordance

When student code raises a recognizable runtime error, an inline ? What does this mean? button appears next to the output line. Clicking it expands a plain-English explanation drawn from a per-language dictionary covering common errors across Python, JavaScript, Java, C++, SQL, Scheme, and Prolog (e.g., NameError, NullPointerException, segmentation fault, no such table). The explanation is also appended to the Suggestions tab so it remains visible after the console scrolls.

Infinite-Loop Watchdog

Every Run click immediately displays a banner explaining how to recover if the page freezes. For runtimes that yield to the event loop (worker-based C++, async paths), a 5-second toast and a 15-second console message with a Reload page button also fire.

Inspector Panel

A bottom-panel Inspector tab is populated automatically after every run with three sub-views:

• Variables — top-level variable names, types, and values captured from the student’s code (supported for Python via Brython and Pyodide, JavaScript, and others where the runtime permits introspection).
• Additional sub-views for structured output and suggestions.

Keyboard Shortcut Overlay

Press ? (or Help → Keyboard Shortcuts) to open a focus-trapped modal listing all available shortcuts.