I'm a solo developer from Japan running S-Hub, a portfolio of 17 Chrome extensions. Over the past year, I've built tools for digital wellbeing, productivity, e-commerce, and Japan-specific use cases.
In this post, I'll share what I built, why I built them, and the lessons I learned along the way.
The Numbers
- 17 extensions published
- 350+ total users
- 8 languages supported per extension
- $0 external development costs (all client-side processing)
- 1 developer (me)
Why 17 Extensions?
It started with solving my own problems. I was frustrated with YouTube Shorts hijacking my feed. Then I wanted a cleaner Twitter experience. Then I needed a prompt manager for AI tools.
Each extension began as a personal itch I needed to scratch. The philosophy: if it bothers me, it probably bothers others too.
The Extensions (by Category)
🧘 Digital Wellbeing
Shorts Killer — My Most Popular Extension
The Problem: YouTube Shorts are designed to be addictive. I'd open YouTube to watch one tutorial and end up scrolling Shorts for 30 minutes.
The Solution: Block Shorts from your home feed, search results, and recommendations. Optionally redirect Shorts to the regular video player with full controls.
Key Features:
- Hide Shorts everywhere on YouTube
- Redirect Shorts to regular player
- Whitelist specific channels
- 100% free, no tracking
Users: 120+ | Rating: 5.0 ⭐
X Detox — Take Back Your Timeline
The Problem: Twitter's "For You" algorithm kept showing me content I didn't ask for. Trending topics were distracting. Promoted tweets everywhere.
The Solution: Force the chronological "Following" timeline. Hide trends, promoted content, and "Who to follow" suggestions.
Key Features:
- Remove "For You" tab
- Hide trending sidebar
- Block promoted tweets
- Clean, distraction-free X experience
Users: 10+ | Rating: 5.0 ⭐
🚀 Productivity
PromptStash — AI Prompt Manager
The Problem: I was copying and pasting the same prompts into ChatGPT, Claude, and Gemini every day.
The Solution: Save, organize, and instantly insert prompts with slash commands. Supports 19+ AI services.
Key Features:
- Slash commands (
/to search and insert) - Template variables (
{{name}},{{date}}) - Prompt chains for multi-step workflows
- Quality scoring to improve your prompts
- Works with ChatGPT, Claude, Gemini, Perplexity, DeepSeek, and more
Users: 5+ | Rating: 5.0 ⭐
DataPick — No-Code Web Scraper
The Problem: I needed to extract data from websites but didn't want to write scrapers for one-off tasks.
The Solution: Point-and-click web scraping. Click on the data you want, and DataPick finds all similar elements. Export to CSV, Excel, or Google Sheets.
Key Features:
- Visual element selection
- Smart pattern detection
- Multiple export formats
- No coding required
Users: 50+ | Rating: 5.0 ⭐
ReadMark — Never Lose Your Reading Position
The Problem: I'd be reading a long article, close the tab, and forget where I was.
The Solution: Auto-save your scroll position on any webpage. When you return, you're right where you left off.
Key Features:
- Automatic position saving
- Works on any webpage
- Share reading positions with others
- All data stored locally
Users: 5+ | Rating: 5.0 ⭐
SnippetVault — Code Snippet Manager
The Problem: I kept losing useful code snippets across different projects and browser tabs.
The Solution: Save code snippets with syntax highlighting, organize with tags, and insert with slash commands.
Key Features:
- Syntax highlighting for 50+ languages
- Tag-based organization
- Slash command insertion
- One-click copy
PageMemo — Notes for Any Webpage
The Problem: I wanted to leave notes on specific webpages without using a separate app.
The Solution: Save notes attached to any URL. When you revisit the page, your notes appear automatically.
Key Features:
- URL-bound notes
- Auto-display on revisit
- No account required
- 100% local storage
ZenRead — Distraction-Free Reading
The Problem: Most websites are cluttered with ads, sidebars, and pop-ups.
The Solution: Transform any webpage into a clean reading view with customizable fonts and bionic reading support.
Key Features:
- Distraction-free reading mode
- Speed reading with bionic text
- Customizable fonts and themes
- Reading streaks to build habits
DataBridge — Visual Data Transfer
The Problem: Copying data between websites often meant losing formatting.
The Solution: Copy structured data from one webpage and paste it into another with visual matching.
ReShapic — Browser-Based Image Processing
The Problem: I didn't want to upload images to random websites just to resize them.
The Solution: Resize, convert, and process images entirely in your browser. No upload, no cloud processing.
Key Features:
- Resize, crop, convert images
- Supports JPEG, PNG, WebP
- All processing happens locally
- Privacy-first design
🛒 E-Commerce Tools
楽天セラーズ (Rakuten Sellers) — Rakuten Market Research
The Problem: Japan's Rakuten marketplace had no equivalent to Helium 10 or Jungle Scout.
The Solution: Keyword research, competitor analysis, and profit calculator specifically for Rakuten Japan sellers.
Key Features:
- Keyword search volume estimation
- Competition level analysis (5 levels)
- Price range visualization
- Profit calculator with Rakuten fees
Users: 20+ | Rating: 5.0 ⭐
Arbitra — Price Comparison for Resellers
The Problem: Japanese resellers ("せどり") needed to compare prices across Amazon, Mercari, and Yahoo Auctions.
The Solution: One-click price comparison across multiple marketplaces with instant profit calculation.
Key Features:
- Cross-platform price comparison
- Amazon, Mercari, Yahoo Auctions support
- Profit margin calculator
- Historical price trends
Users: 20+ | Rating: 5.0 ⭐
🇯🇵 Japan-Specific Tools
物件カウンター 賃貸 (Property Counter - Rental) — SUUMO Rental Analyzer
The Problem: Apartment hunting in Japan on SUUMO (the largest real estate site) was tedious.
The Solution: Auto-count and compare rental properties. Analyze rent averages by area.
物件カウンター 購入 (Property Counter - Buy) — SUUMO Purchase Analyzer
The Problem: Home buyers needed to compare properties and calculate price per tsubo (Japanese unit).
The Solution: Property price analysis with tsubo calculations and area comparisons.
Yahoo快適モード (Yahoo Comfort Mode) — Clean Yahoo! JAPAN
The Problem: Yahoo! JAPAN is cluttered with low-quality articles and ads.
The Solution: Filter out ads and clickbait content for a cleaner browsing experience.
TVer Plus — Enhanced TVer Viewer
The Problem: TVer (Japan's free TV streaming) lacked playback controls.
The Solution: Add playback speed control, picture-in-picture, and keyboard shortcuts.
Japanese Font Finder — Identify Fonts on Any Webpage
The Problem: Existing font detection tools couldn't identify Japanese fonts.
The Solution: Detect 150+ Japanese fonts including Yu Gothic, Hiragino, Noto Sans JP, Morisawa, and Fontworks families.
Users: 30+ | Rating: 5.0 ⭐
What I Learned
1. Marketing is 100x Harder Than Building
Building 17 extensions took time, but getting users is the real challenge. You can have the best product, but if no one knows about it, it doesn't matter.
What works:
- Reddit communities (r/nosurf, r/productivity, r/chrome)
- Dev.to and technical blog posts
- Localization (8 languages = 8x search visibility on Chrome Web Store)
What doesn't work:
- Just publishing and hoping
- Paid ads (for indie extensions)
2. Localization is a Superpower
Every extension supports 8 languages: English, Japanese, Spanish, Portuguese, Korean, German, French, and Italian.
This isn't just good UX—it's an SEO advantage. Chrome Web Store indexes each language separately, so 17 extensions × 8 languages = 136 searchable listings.
3. Zero External Costs is Possible
All my extensions run entirely client-side:
- No backend servers
- No database costs
- No API fees
- No ongoing operational expenses
The only costs are the $5 Chrome Web Store developer fee and my time.
4. Solve Your Own Problems First
Every extension started as a tool I built for myself. This has two benefits:
- You understand the problem deeply
- You're your own first user and tester
5. The "Keyword Stuffing" Lesson
My first submission of PromptStash was rejected for "keyword stuffing" in the description. Chrome Web Store is strict about this. Keep descriptions natural—don't list keywords.
Tech Stack
All extensions share the same foundation:
- Framework: React + TypeScript
- Build: Vite + CRXJS
- Styling: Tailwind CSS
- Monetization: ExtensionPay (for premium features)
- Localization: 8 languages via _locales
What's Next
- Product Hunt launches for top extensions
- Cross-promotion between extensions
- More automation with n8n for marketing
- Reaching 1,000 total users
Try Them Out
All extensions are available on Chrome Web Store. Most are free, some have optional premium features.
🌐 Portfolio: S-Hub Extensions
If you find any of these useful, a review on the Chrome Web Store would mean a lot!
Questions?
I'm happy to answer questions about building Chrome extensions, the tech stack, monetization strategies, or anything else. Drop a comment below!
Tags: #chrome #extensions #webdev #productivity #javascript #typescript #react
Top comments (0)