# DOM Time Machine Pro

> A powerful developer tool designed to capture a high-fidelity, chronological record of a webpage's DOM state. Capture, rewind, and inspect the code of a page at any point in time.

Canonical page: [https://chrome-stats.com/d/dom-time-machine-pro](https://chrome-stats.com/d/dom-time-machine-pro)

## Overview

- **ID:** `dom-time-machine-pro`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** scolastico
- **Category:** web-development
- **Daily users:** 2
- **Weekly downloads:** 1
- **Version:** 1.0.4
- **Last updated:** 2026-01-31
- **First published:** 2026-01-28
- **Size:** 18 KB
- **Data as of:** 2026-09-15
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/dom-time-machine-pro/)
- **Website:** [https://github.com/scolastico-dev/dom-time-machine/issues](https://github.com/scolastico-dev/dom-time-machine/issues)

## Description

<strong>DOM Time Machine Pro</strong> is a powerful developer tool designed to capture a high-fidelity, chronological record of a webpage's DOM state. Unlike standard screen recording, this extension captures the actual HTML structure and associated assets, allowing you to "rewind" and inspect the code of a page at any point in time.

Why It’s Useful
<ul><li><strong>Debug Transient UI:</strong> Capture elusive states like toast notifications, hover effects, or race conditions that disappear before you can inspect them.</li><li><strong>State Analysis:</strong> Compare how the DOM evolves after specific user actions or API responses.</li><li><strong>Portable Recordings:</strong> Export your session as a JSON file to share with other developers or import later for further analysis.</li><li><strong>Asset Persistence:</strong> Automatically inlines CSS and converts images to Base64 to ensure the recording remains intact even if the original website goes offline.</li></ul>
How It Works

The extension utilizes three distinct capture modes to suit different needs:
<ol><li><strong>Debounced (Mutation):</strong> Uses a <code>MutationObserver</code> to trigger a snapshot whenever the DOM changes, with a 100ms debounce to maintain performance.</li><li><strong>RequestAnimationFrame:</strong> Captures the DOM at the browser's refresh rate—useful for high-speed animations.</li><li><strong>MozAfterPaint (Firefox Recommended):</strong> Specifically designed for Firefox, this mode triggers a capture only after the browser actually paints a change to the screen.</li></ol>
<strong>Workflow:</strong>
<ul><li><strong>Record:</strong> Select a mode from the popup to begin. The extension icon will turn red to indicate active recording.</li><li><strong>Capture:</strong> The background script manages the storage of snapshots and assets while you navigate.</li><li><strong>View:</strong> Once stopped, a dedicated "Viewer" tab opens. Use the slider or navigation buttons to travel through your recording timeline.</li></ul>
Browser Recommendation

While compatible with Chromium-based browsers, <strong>Firefox is highly recommended</strong>. Firefox supports the <code>MozAfterPaint</code> event (when enabled in <code>about:config</code>), which provides the most efficient and accurate "paint-based" recording triggers available.

Installation &amp; Configuration

For Firefox users wanting to use the Paint mode:
<ol><li>Navigate to <code>about:config</code>.</li><li>Set <code>dom.send_after_paint_to_content</code> to <code>true</code>.</li></ol>
License

This project is licensed under the <strong>GNU Affero General Public License (AGPL-3.0)</strong>. We believe in open-source collaboration and ensuring that any improvements to this tool remain available to the community.

## Rankings

- #67,737 — Overall
- #67 — machine
- #240 — cmd+m (mac)

## Permissions and access

### Permissions

- `storage`
- `unlimitedStorage`
- `activeTab`
- `scripting`
- `tabs`

## Safety

- **Risk impact:** Moderate risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/dom-time-machine-pro)