A fully offline, zero-dependency code analysis tool that runs entirely in your browser.
Drop in your JavaScript, HTML, or CSS — get deep static analysis, performance profiling, accessibility auditing, memory leak detection, scope visualization, and dependency graphs. No install. No internet. No build step.
| Module | What it does |
|---|---|
| Static Analyzer | Hand-written AST engine — catches unused vars, complexity issues, promise errors, and 14 other rules |
| Scope Visualizer | Interactive canvas diagram of your full scope chain and closure references |
| Performance Profiler | Flame chart + long-task detection via sandboxed iframe execution |
| Accessibility Auditor | WCAG 2.1 AA checks — contrast ratios, ARIA, labels, heading order |
| Memory Leak Detector | WeakRef + Proxy instrumentation to catch detached nodes, listener leaks, and growing collections |
| Dependency Graph | Force-directed module graph with cycle detection |
| Live Sandbox | Step-through execution with breakpoints and live variable inspection |
No installation required. Just clone and open.
git clone https://github.com/gyanaprakashkhandual/devlens.git
cd devlens
python3 -m http.server 8080Open http://localhost:8080 in your browser.
Note: Opening
index.htmldirectly viafile://will block Web Workers in Chrome. Use the local server above for full functionality. Firefox works fine withfile://.
- Drop or paste your
.js,.html,.css, or.jsonfiles onto the drop zone - Pick a module from the left sidebar
- Read findings — each one links back to the exact line in your code
- Edit and re-analyze without leaving the tool
- Export a report as a standalone
.htmlfile — works fully offline
| Action | Shortcut |
|---|---|
| Open files | Ctrl/Cmd + O |
| Re-analyze | Ctrl/Cmd + Shift + Enter |
| Switch modules | Ctrl/Cmd + 1–7 |
| Find in editor | Ctrl/Cmd + F |
| Generate report | Ctrl/Cmd + Shift + R |
| Toggle dark mode | Ctrl/Cmd + Shift + D |
Pure vanilla — no frameworks, no libraries, no build tools.
- HTML5 / CSS3 — cascade layers, custom properties, grid, flexbox
- JavaScript ES2022+ — modules, workers, proxies, async iterators, WeakRef
- Web Workers — all heavy analysis runs off the main thread
- Canvas 2D API — scope diagrams, flame charts, dependency graphs
- IndexedDB — full session persistence across page reloads
Total JS payload: under 120KB unminified.
| Browser | Version |
|---|---|
| Chrome / Edge | 105+ |
| Firefox | 105+ |
| Safari | 16+ |
Long-task detection in the profiler requires a Chromium browser. All other modules work across all supported browsers.
Works anywhere static files are served — no server-side code needed.
- Local:
python3 -m http.server 8080 - GitHub Pages / Netlify / Vercel / Cloudflare Pages: upload the folder as-is
- Air-gapped / USB: copy the folder, run a local server on the target machine
MIT — free to use, modify, and distribute.
Built for developers who want professional-grade tooling without the toolchain.