Modify

Modify Icon
Main Chat - Light Theme
Main Chat - Dark Theme
Element Selector
Group Creation - Dark Theme
Curated Modifications - Light Theme
Modification Details - Light Theme
Code Editor - Light Theme

Inspiration

We were frustrated by the browser extension bloat. Needing separate extensions to hide YouTube comments, another to change fonts, another to remove annoying popups or adblock. Each tiny customisation required trusting yet another extension. We wanted one tool that could do it all: modify any website ANY way we want, without writing code, and have those changes persist.

What it does

Modify is a Chrome extension that lets you customize any website using natural language. Simply describe what you want to change, and AI generates and executes the JavaScript to make it happen without coding required.

Core Features

Natural Language Modifications

Type what you want in plain English:

"Hide the comments section"
"Make all text purple"
"Remove the sidebar"
"Add a dark mode toggle"

The extension understands your intent, analyses the webpage structure, and generates precise JavaScript to accomplish the task.

Intelligent Element Selection

Don't want to describe elements? Use the Select Element tool:

Click the crosshair button
Click on any element(s) on the page, they highlight as you hover
Selected elements appear in the prompt area
Scroll up or down to control the selected area's granularity
Type your modification (ex, "make this red" or "hide these")
The extension then uses the exact CSS selectors for precision

Image Upload Support

Upload your own images to use in modifications:

Set custom page backgrounds
Replace logos or icons
Add decorative elements

Voice Input

Click the microphone button to speak your modification request, for more accessibility / ease of use.

Persistent Modifications

Every modification you create:

Automatically reapplies when you revisit the page
Can be enabled/disabled without deleting
Stores the original prompt for reference
Can be tied to any site, URL pattern, or group

Smart URL Pattern Matching

Control where your mods apply:

Current Website: Applies to all pages on the same domain (e.g., youtube.com/*)
All Websites: Applies everywhere (*)
Custom Patterns: Specify exact URL patterns
Groups: Apply to predefined website collections

Groups

Organize websites into groups for batch modifications:

Create groups like "Social Media", "News Sites", "Work Tools"
Add website URLs to each group
Choose a group as your target and the mod applies to all sites in that group
Custom icons for visual organization

Undo System

Made a mistake? Click Undo to:

Disable the last modification
Restore your prompt, selected elements, and uploaded images
Refresh the page to its original state

Curated Modifications

We've included a list of Curated Modifications that we think are really cool! Check them out in the video and image gallery.

For Technical Users

Developers and power users can view and edit the generated JavaScript directly:

Open the Mods panel to see all saved modifications
Click on any mod to view its generated code
Edit the code manually for fine-grained control
Describe code improvements
Changes are saved and reapplied automatically

Settings & Configuration

Bring Your Own API Key

Modify uses OpenRouter for AI access:

Enter your own OpenRouter API key
Connection status indicator shows green when connected, red when not

Use Cases

Accessibility

Enlarge text on hover for users with vision impairments
Increase contrast on low-contrast websites
Convert small fonts site-wide to a readable minimum size
Add dyslexia-friendly fonts like OpenDyslexic to any site
Remove animations for users with vestibular disorders

Parental Controls & Safety

Blur or hide inappropriate content based on keywords
Remove comments sections to avoid toxic discussions
Add time-on-page warnings to limit screen time

Productivity & Focus

Hide social media feeds while keeping messaging accessible
Add Pomodoro timers to any website
Highlight deadlines on project management tools
Remove cookie banners and popups permanently
Hide YouTube Shorts to stay focused on long-form content

Customization & Aesthetics

Apply custom color themes to any website
Add dark mode to sites that don't have it
Redesign navigation menus to your preference
Replace logos or backgrounds with custom images

Education & Learning

Turn YouTube videos into interactive quizzes using AI
Highlight key terms in educational content
Add note-taking sidebars to any article

The possibilities are endless :)

How we built it

Chrome Extension Manifest V3 architecture
TypeScript for type-safe development
Tailwind CSS for the popup UI
OpenRouter API for multi-model AI access
Chrome Storage API for persistence
Message passing between popup, background service worker, and content scripts
MutationObserver for dynamic element detection
Trusted Types for CSP-compliant code injection

AI was used to assist development: Claude Code & Cursor.

Challenges we ran into

Content Security Policy (CSP)

Modern websites like YouTube and Twitter use strict CSP that blocks eval(), innerHTML, and inline scripts. We solved this by:

Injecting into the MAIN world instead of the isolated content script world
Creating a Trusted Types policy to bypass innerHTML restrictions
Using document.createElement() patterns instead of HTML strings

Race Conditions

When a user executes a modification, the page might trigger a reapply of saved scripts. We implemented a debounce mechanism to prevent the reapply from overwriting the user's fresh modification.

Dynamic SPAs

Single Page Applications don't trigger full page reloads. We detect URL changes and intelligently reapply or regenerate scripts as needed.

Image Persistence

Browser extensions can't access the filesystem. We convert uploaded images to base64 data URLs and store them with the script, allowing images to persist and reapply.