zstack — spin your DOM in z-space

Explode the current page into its z-index / stacking layers and orbit them in 3D. Catch z-index felonies at a glance.

See the invisible layers of any web page. zstack explodes the page you're looking at into its z-index / stacking layers and floats them in 3D — so you can finally see which element sits on top of what, and why. It's a forensic tool for the stacking bugs you can't catch in flat DevTools: the menu that hides behind a banner, the modal that won't come to the front, the z-index: 999999 arms race buried in someone else's CSS. Click the toolbar icon on any page and zstack takes it apart into stacked planes — one per stacking layer, front to back. What you can do • Fly a camera through the layers in 3D, or flip to a flat 2D grid to scan every layer at a glance (press V). • Paint mode draws the real backgrounds, images, SVGs and text on each layer; wire mode shows glowing labelled outlines (press P). • Open a side report panel listing every layer and every element on it — click any item to jump straight to the live element in DevTools and light it up in the stack (press L). What it catches 🚨 Absurd z-index values — anything ≥ 100,000 is flagged as a red "felony" layer. 🗜️ Silently clamped values — browsers cap z-index at ~2.1 billion, so z-index: 1600000000000000000 quietly becomes 2147483647. zstack reads your original CSS and shows the clamp. 🔇 z-index that does nothing — a z-index on a position: static element is ignored by the browser; zstack points it out. 🧬 Why each layer exists — transform, opacity, filter, will-change, position, and more. Private by design Everything runs locally in your browser. zstack reads the page only when you click it, uses just the activeTab and scripting permissions, requests no host access, runs no remote code, and sends nothing anywhere. No accounts, no tracking, no servers. Free and open source (MIT). Works in Chrome, Brave, and other Chromium browsers.