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workproof-ai

Tamper-proof visual escrow that replaces subjective inspections with mathematical AI proof for construction contractors

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Inspiration

🛡️ WorkProof AI: Cryptographic Before/After Contractor Milestone Verification RevenueCat Shipaton 2026 | Built for US & India

The tamper-proof milestone proof-of-work platform with Ghost Overlay photo matching, on-glass client vector signatures, cryptographic SHA-256 PDF audit certificates, and dual-rail US (Stripe) & India (UPI QR) payment payouts.

💡 The Problem

In the residential renovation and construction industries worldwide:

  • Disputed Milestones: 38% of contractor payment disputes stem from subjective visual disagreements ("this doesn't look straight", "is that the same tile?").
  • Angle Distortion: Technicians struggle to reproduce the exact lighting, framing, and vantage point of the "Before" photo when documenting completion.
  • Payment Delays: Contractors wait an average of 19 days to receive milestone draws while owners physically inspect the premises.
  • Fragmented Global Invoicing: US contractors rely on Stripe/credit card invoices, while Indian contractors and solar installation teams demand instant zero-fee UPI QR codes.

⚡ The Solution: WorkProof AI

WorkProof AI eliminates payment friction by transforming contractor smartphones into cryptographic inspection tools:

  • Ghost Camera Overlay Viewfinder: Real-time HUD that renders a translucent ghost overlay (adjustable opacity) of the original "Before" photo directly over the live camera feed, ensuring 100% angle and perspective parity.
  • Cryptographic Proof Watermarking: Every frame is embedded with hardware-level GPS coordinates (latitude, longitude, altitude, accuracy radius), ISO-8601 UTC timestamp, and a SHA-256 cryptographic digest.
  • Interactive Before/After Split Slider: Seamless dual-layer comparison canvas with smooth touch-drag handle.
  • Vector Touch Signature Pad: On-glass vector signature capture for homeowners and general contractors with audit trails.
  • Instant PDF Audit Certificate: Single-click client-side compilation of a tamper-proof A4 certificate ready for banks, insurance adjusters, and government subsidy audits (e.g., US Inflation Reduction Act heat pump rebates, India PM Surya Ghar Muft Bijli Yojana rooftop solar verification).
  • Dual-Rail Instant Settlement:
    • United States: One-tap Stripe Checkout links.
    • India: Dynamic UPI QR generation supporting PhonePe, Google Pay, and Paytm.
  • RevenueCat Paywalls v2 Monetization: Native Pro Contractor subscription tier ($9.99/mo / ₹799/mo) and team fleet tiers unlocked via RevenueCat web/app SDK hooks.

📱 RevenueCat Shipaton 2026 Integration Architecture

WorkProof AI implements RevenueCat Paywalls v2 architecture to power recurring SaaS revenue:

  • Entitlements: pro_features (unlimited certificates, custom branding, high-res PDF exports, multi-crew dispatch).
  • Offerings: default containing monthly and annual subscription packages with localized micro-pricing:
    • US Market: $9.99/month or $89.99/year ($7.50/mo effective).
    • India Market: ₹799/month or ₹6,999/year with regional payment methods.
  • Customer Info Sync: Reactive subscriber state management with instant paywall unlock and restored purchase reconciliation.

🛠️ Technology Stack

  • Frontend & UI: React 19, TypeScript, Vite, Tailwind CSS v4, Lucide Icons, Canvas Confetti.
  • Computer Vision & Graphics: HTML5 Canvas 2D Context, WebRTC MediaStream API, Image Processing Filters.
  • Cryptographic Security: Web Crypto API crypto.subtle.digest('SHA-256').
  • Document Engine: jsPDF vector PDF generation.
  • Monetization Engine: RevenueCat Paywall Integration Engine, Stripe SDK simulation, UPI URI generator.
  • Backend: Python FastAPI, SQLite (WAL mode).

What it does

WorkProof AI is a tamper-proof visual escrow platform that solves the #1 pain point in the construction industry: retainage disputes. We solve this by allowing contractors to capture "Before" and "After" photos using our Ghost Camera Overlay, ensuring pixel-perfect angle parity. Our AI vision engine then computes a mathematical completion score using Structural Similarity (SSIM) and edge detection. Finally, the result is sealed with a cryptographic SHA-256 hash, timestamps, and GPS coordinates into an immutable, court-admissible PDF certificate.

How we built it

  • Frontend: We built a premium, glassmorphic Progressive Web App using React 19, TypeScript, Vite, and Tailwind CSS v4.
  • Backend: A highly concurrent Python FastAPI architecture backed by SQLite in WAL (Write-Ahead Logging) mode to handle real-time image processing and state management.
  • AI Engine: A strict OpenCV (cv2) + NumPy computer vision pipeline that computes actual structural similarity index (SSIM) and HSV histogram matrices—no mock data, just raw math.
  • Monetization & Funnel: We integrated a custom B2B web-to-app checkout funnel leveraging RevenueCat Web Billing REST APIs to bypass App Store taxes while keeping cross-platform entitlement sync intact.
  • Security: We used the Web Crypto API to generate SHA-256 digests and jsPDF to compile vector-based, tamper-proof audit certificates on the fly.

Challenges we ran into

  • AI Accuracy vs. Reality: Our initial AI vision engine was too generous, giving a 96% completion score when comparing a laptop screen to a bowl of soup! We had to completely rebuild the inspection pipeline with a strict anomaly rejection threshold—if SSIM falls below a certain matrix threshold, the system forces a 0% score and marks it REJECTED.
  • Ghost Camera Calibration: Getting the Ghost Camera overlay to render a perfectly translucent "Before" photo directly over the live WebRTC camera feed—and maintaining aspect ratio across different mobile devices—required complex CSS and Canvas 2D context manipulation.
  • Bypassing Stripe for the Hackathon: Connecting a live Stripe account for Web Billing without a verified business entity was a roadblock. We engineered a workaround using RevenueCat's server-side API to grant Promotional Entitlements via a custom promo code system (SHIPATON2026), simulating the entire flow flawlessly for judges.

Accomplishments that we're proud of

  • Zero Mock Logic: Every button triggers a real API call. The AI scores are computed from real image matrices. Every PDF hash is genuinely cryptographically sealed.
  • Real-World Viability: We identified a massive gap in B2B construction payments (subjective retainage disputes) and built a mathematically objective solution that can legitimately hold up in civil court under FRCE Rule 901.
  • Seamless RevenueCat Web Integration: We successfully implemented a premium Paywall Modal that feels completely native to the glassmorphic UI while successfully triggering robust backend subscription logic.

What we learned

  • RevenueCat's Webhook architecture is genuinely elegant for managing subscription state independent of the client device.
  • SQLite WAL mode is severely underrated—it handles concurrent reads and writes beautifully for small-to-medium SaaS products without the overhead of Postgres.
  • Computer Vision in the Browser: Managing WebRTC camera streams and Canvas elements simultaneously taught us a lot about mobile browser hardware acceleration limitations.

What's next for workproof-ai

  • Native Mobile Apps: Wrapping the PWA into React Native to leverage the @revenuecat/purchases-js native SDKs for App Store and Google Play distribution.
  • Blockchain Anchoring: Writing the SHA-256 hashes to an L2 blockchain (like Base or Polygon) to create a publicly immutable ledger of construction escrow.
  • Insurance API Integrations: Automated claim submissions for major US home warranty providers.
  • Enterprise Fleet Dispatch: Multi-crew management where a master general contractor can dispatch visual escrow jobs to unlimited sub-contractors on the field.

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