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Jewelry Deal Evaluator - Chrome Extension
Target Launch: January 2025 Status: Core MVP functional, freemium implementation pending
Problem
People buying/selling jewelry online can't quickly assess value or authenticity. Scams and overpricing are common. Professional appraisals cost $50-150 per item.
Solution
Chrome extension using Gemini Nano for on-device jewelry analysis. Privacy-preserving (images/data never leave device). Compares asking price against material value using live metal prices.
Target Users
- Online jewelry buyers (eBay, Etsy, Facebook Marketplace, Blue Nile)
- Casual sellers wanting to price items
- Value-conscious shoppers (not pure luxury buyers)
- Estimated SAM: 25M users (Chrome users, US/EU/UK, willing to install extensions)
Current State (from repo)
Working:
- ✅ Gemini Nano integration (auto-downloads model)
- ✅ Page content extraction (multilingual: EN, PT, ES, FR)
- ✅ Live gold prices via FreeGoldAPI
- ✅ Currency conversion via Frankfurter (ECB)
- ✅ VAT-aware calculations by country
- ✅ Multi-step loading indicators
- ✅ Dark "Luxury Intelligence" themed overlay
- ✅ Caching (prices: 15min, analysis: 60min)
- ✅ History feature (stores evaluations)
- ✅ Alerts-service backend structure (Hono, SQLite, Puppeteer)
Pending for launch:
- [ ] Freemium gating (3 analyses/day free)
- [ ] Stripe payment integration
- [ ] Chrome Web Store submission
- [ ] Test on 10+ jewelry sites
- [ ] Confidence indicator display
- [ ] Manual value override
Tech Stack
Extension:
- Chrome Extension (Manifest V3)
- Gemini Nano (on-device AI, Chrome 138+)
- Service Worker + Content Script pattern
- Chrome Storage API (caching, history)
Backend (alerts-service):
- Hono (API framework)
- SQLite (better-sqlite3)
- Puppeteer (price monitoring scraping)
- node-cron (scheduled checks)
- Resend (email notifications)
- web-push (browser notifications)
- Caddy (reverse proxy, auto HTTPS)
- Docker + Hetzner VPS (~€4/mo)
Payments: Stripe
Revenue Model - FREEMIUM
Free Tier
| Feature | Limit |
|---|---|
| Analyses per day | 3 |
| Verdict | Basic (Excellent/Fair/Overpriced) |
| Currency | Auto-detected only |
| VAT breakdown | Hidden |
| History | Last 5 evaluations |
| Price alerts | None |
Premium ($19.99/year or $3.99/month)
| Feature | Access |
|---|---|
| Analyses | Unlimited |
| Verdict | Full 6-tier with multiplier |
| Currency | All 30+ countries |
| VAT breakdown | Full breakdown |
| History | Unlimited + search |
| Export | PDF + CSV |
| Price alerts | Up to 20 items |
Business Projections (from analysis)
| Year | Users | Paid (3%) | Revenue | Net Profit |
|---|---|---|---|---|
| 1 | 5,000 | 150 | $3,000 | $2,700 |
| 3 | 75,000 | 2,250 | $45,000 | $40,500 |
| 5 | 250,000 | 7,500 | $150,000 | $135,000 |
Cost structure: Near-zero (client-side AI, free APIs, ~€4/mo VPS) Gross margin: ~95%
Competitive Landscape
- Direct competitors: None identified (novel approach)
- Indirect: Manual calculations, $50-150 appraisals, generic price comparison tools
- Moat: First mover, local AI = no server costs, privacy-preserving
Implementation Phases (from FREEMIUM_SPEC)
Phase 1: Core Gating - PRIORITY FOR JAN LAUNCH
- [ ] Add usage tracking to chrome.storage
- [ ] Implement daily limit check
- [ ] Add feature gate module
- [ ] Simplify verdict for free tier
- [ ] Hide premium UI elements
- [ ] Add "limit reached" modal
- [ ] Add "upgrade" prompts
Phase 2: Authentication
- [ ] Login/register UI in extension
- [ ] JWT storage and refresh
- [ ] /auth endpoints in alerts-service
Phase 3: Stripe Integration
- [ ] Set up Stripe products/prices
- [ ] /subscription/* endpoints
- [ ] Webhook handler
- [ ] Checkout flow from extension
Phase 4: Premium Features
- [ ] Full verdict for premium
- [ ] VAT breakdown
- [ ] Country selector
- [ ] Unlimited history + search
- [ ] PDF/CSV export
Phase 5: Price Alerts
- [ ] Watches CRUD
- [ ] Price checker job
- [ ] Push/email notifications
Key Risks
| Risk | Mitigation |
|---|---|
| Metal price APIs shut down | Multiple fallbacks, cached prices |
| Chrome policy changes | Firefox/Safari ports ready |
| LLM accuracy complaints | Confidence indicators, disclaimers |
| Google builds competing feature | First mover advantage, brand loyalty |
Blockers
- None critical - main work is freemium implementation + store submission
Validation Scores (based on BUSINESS_ANALYSIS.md)
| Criterion | Score | Notes |
|---|---|---|
| Competition | 5/5 | No direct competitors, novel approach |
| Willingness to Pay | 4/5 | Jewelry = high-value decisions, appraisals cost $50-150 |
| Feasibility | 4/5 | MVP working, freemium is incremental |
| Privacy Angle | 5/5 | On-device AI is core differentiator |
| Personal Interest | ?/5 | TBD |
| Total | 18+/25 | Strong candidate |
Links
- Repo: /Users/paulspende/Documents/paul/repos/jewelry-evaluator
- Docs: See repo /docs folder (BUSINESS_ANALYSIS.md, FREEMIUM_SPEC.md, FEATURE_BRAINSTORM.md)
Progress Log
- 2025-01-05: Brief updated with full project details from repo
- 2025-01-05: Core MVP confirmed functional
- 2025-01-05: Freemium spec exists, implementation pending