ChatGPT vs Claude vs Gemini: Which AI Builds the Best Chrome Extension?

The Challenge

I asked all three AI powerhouses to build the same Chrome extension: A Focus Mode Blocker that blocks distracting websites with a single click and tracks your productive time.

Requirements:

• One-click to enable/disable focus mode
• Block popular distracting sites (social media, YouTube, etc.)
• Track total focus time
• Clean, intuitive interface
• Custom site blocking capability

Let's see which AI delivered the best results.

Round 1: Understanding the Task

ChatGPT 🟢

Response Time: Fast Understanding: Immediately grasped the concept and asked clarifying questions about features like "Should it have a timer?" and "Do you want sound notifications?"

Score: 9/10 - Asked smart questions but sometimes over-complicated things.

Claude 🔵

Response Time: Fast Understanding: Understood perfectly and suggested additional features I hadn't considered, like "productive sites whitelist" and "daily focus streak tracking."

Score: 10/10 - Best at understanding user intent and suggesting improvements.

Gemini 🔴

Response Time: Fast Understanding: Got the basics but needed more back-and-forth to clarify the blocking mechanism and UI preferences.

Score: 7/10 - Functional understanding but less intuitive.

\Round 2: Code Quality

ChatGPT 🟢

What It Generated:

• Clean manifest.json (Manifest V3)
• Background service worker for blocking logic
• Popup HTML with toggle button
• Basic CSS styling

Strengths:

• Well-commented code
• Used modern Chrome Extension APIs correctly
• Included error handling

Weaknesses:

• Generic variable names in places
• CSS was functional but not impressive
• Forgot to include the timer feature initially

Code Quality Score: 8/10

Claude 🔵

What It Generated:

• Complete manifest.json with all permissions
• Sophisticated background worker with pattern matching
• Beautiful popup with gradient UI
• Local storage implementation for stats
• Bonus: Options page for customization

Strengths:

• Production-ready code structure
• Excellent variable naming and organization
• Modern, aesthetic UI with animations
• Comprehensive error handling
• Added features I didn't ask for (but needed)

Weaknesses:

• Slightly more complex for beginners
• Could overwhelm with too many features

Code Quality Score: 10/10

Gemini 🔴

What It Generated:

• Basic manifest.json
• Simple blocking logic
• Minimal popup interface
• Limited styling

Strengths:

• Easy to understand for beginners
• Lightweight code
• Quick implementation

Weaknesses:

• Used some deprecated APIs initially
• Had to fix several bugs in testing
• UI looked dated
• Missing timer functionality entirely
• No data persistence

Code Quality Score: 6/10

Round 3: Actually Testing the Extensions

I actually built and tested each extension. Here's what happened:

ChatGPT's Extension 🟢

Installation: Smooth Functionality: Worked on first try! Blocked sites effectively, timer counted correctly.

User Experience: Clean and functional. The toggle worked instantly. Timer displayed in minutes and seconds.

Bugs Found:

• Timer didn't persist after browser restart
• Couldn't add custom sites without editing code

Real-World Score: 8/10

Claude's Extension 🔵

Installation: Smooth with clear instructions Functionality: Flawless. Everything worked, including features I forgot to ask for.

User Experience: Beautiful gradient interface, smooth animations, satisfying click feedback. The options page made customization easy without touching code.

Bugs Found:

• None in core functionality
• One minor CSS alignment issue on smaller screens

Real-World Score: 9.5/10

Gemini's Extension 🔴

Installation: Required some troubleshooting Functionality: Basic blocking worked after fixing manifest errors.

User Experience: Functional but bare-bones. Looked like a 2010 extension. No visual feedback when toggling.

Bugs Found:

• Manifest V2 warnings (outdated)
• Sites sometimes didn't unblock immediately
• Stats didn't save
• Had to manually refresh blocked tabs

Real-World Score: 5/10

Round 4: Explaining the Code

I asked each AI to explain how their extension works.

ChatGPT 🟢

Gave a solid paragraph-by-paragraph breakdown. Good for intermediate developers. Sometimes used jargon without explaining.

Explanation Score: 8/10

Claude 🔵

Provided a masterclass explanation with:

• High-level overview first
• Then detailed component breakdowns
• Analogies for complex concepts
• Even explained WHY certain approaches were chosen

Explanation Score: 10/10

Gemini 🔴

Basic explanation that covered the essentials. Missed explaining some implementation choices. Better for absolute beginners.

Explanation Score: 7/10

Round 5: Iteration & Debugging

I reported bugs and asked for improvements:

ChatGPT 🟢

• Fixed the timer persistence bug quickly
• Added custom site blocking when asked
• Responsive to feedback
• Sometimes needed 2-3 tries to get it right

Iteration Score: 8/10

Claude 🔵

• Fixed the CSS issue immediately with better solution
• Proactively suggested other improvements
• Added dark mode without being asked
• Every iteration made it better

Iteration Score: 10/10

Gemini 🔴

• Upgraded to Manifest V3 after prompting
• Fixed blocking issues but introduced new bugs
• Needed detailed instructions for each fix
• Progress was slow

Iteration Score: 6/10

Final Scores

Category	ChatGPT	Claude	Gemini
Understanding	9/10	10/10	7/10
Code Quality	8/10	10/10	6/10
Real-World Testing	8/10	9.5/10	5/10
Explanations	8/10	10/10	7/10
Iteration	8/10	10/10	6/10
TOTAL	41/50	49.5/50	31/50

The Verdict

🥇 Winner: Claude

Best For: Developers who want production-ready code, beautiful UI, and thoughtful feature suggestions.

Why It Won: Claude didn't just complete the task—it anticipated needs, delivered polished code, and created something you'd actually want to publish. The attention to detail in both functionality and design was unmatched.

🥈 Runner-Up: ChatGPT

Best For: Quick prototypes and reliable, functional code that works on the first try.

Why It's Great: ChatGPT delivered exactly what was asked for with solid execution. Perfect for getting something working fast, though it won't blow you away with extras.

🥉 Third Place: Gemini

Best For: Absolute beginners learning Chrome extension basics.

Why It Falls Short: While functional at a basic level, Gemini produced code that felt dated and required significant debugging. It's learning, but not competition-ready yet for development tasks.

Real Talk: Which Should YOU Use?

Choose Claude if:

• You're building something you plan to publish
• You want clean, maintainable code
• You appreciate good UI/UX
• You want AI that thinks ahead

Choose ChatGPT if:

• You need something working ASAP
• You want reliable, solid fundamentals
• You're comfortable polishing things yourself
• You prefer straightforward implementations

Choose Gemini if:

• You're just learning and want simple examples
• You don't need advanced features
• You're okay troubleshooting
• You want minimal complexity

The Bottom Line

For building Chrome extensions, Claude is the clear winner. It's like having a senior developer on your team who cares about craft. ChatGPT is your reliable colleague who gets stuff done. Gemini is the intern with potential but needs more training.

Want to try this yourself? Copy the exact prompt I used:

"Create a Chrome extension called Focus Mode Blocker. It should: block distracting websites with one click, track total focus time, have a clean popup interface, and allow custom site blocking. Use Manifest V3."

Test all three and see which coding style you prefer!

Which AI do you use for coding? Drop a comment below! 👇