I Let AI Build My Shopify App: Inside ExemptSync

I gave Cursor + Claude full control for 48 hours. Here’s what shipped — including ExemptSync, now live on the Shopify App Store.

TL;DR

AI can scaffold a functional Shopify app in 2 days, but you’ll still need to clean up the edges. ExemptSync is the proof — built with 70% AI-generated code, 30% human refinement.

Try it: ExemptSync on the Shopify App Store

The Experiment

The challenge: Build a production-ready Shopify app without writing a single line of code myself. Everything — architecture, API calls, UI components, even commit messages — generated by AI.

The result: ExemptSync, now approved and live on the Shopify App Store.

The stack: Cursor (Claude Sonnet 4) for code generation, Shopify CLI for scaffolding, Remix + Polaris (Shopify’s standard), 48 hours of AI-driven development.

What ExemptSync Actually Does

Built for U.S. Shopify merchants dealing with tax-exempt customers:

• Branded portal — Customers upload certificates directly
• AI-powered OCR — Extracts data automatically from uploads
• Shopify sync — Approved exemptions sync to customer accounts
• Expiry tracking — Automated reminders keep you compliant

Free plan available. I built this because I was tired of hearing merchants complain about managing tax exemptions manually.

Hour 0–2: The Setup

Cursor generated a clean app.tsx scaffold. Shopify authentication wired up (OAuth handshake, session tokens) on the first attempt. Prisma schema for certificates, customers, and exemption records — all generated.

Verdict: AI understood Shopify’s auth pattern and generated working OAuth handshake on first try.

Hour 2–6: The Core Logic

What worked: Customer-facing upload portal, admin dashboard for reviewing submissions, basic file storage integration. All generated with minimal prompting.

What didn’t: AI suggested storing certificates in local filesystem (not scalable). Didn’t account for multi-state compliance rules. Tried to use deprecated Shopify API endpoints.

The fix: Had to intervene with ‘Use Shopify’s file API, not local storage. Use modern OCR service with fallback.’ AI corrected course immediately.

Hour 6–12: The UI

This is where AI shined. Polaris components are well-documented, and AI generated a complete admin interface — data tables, status badges, modal forms — that looked production-ready out of the box.

Hour 12–24: The Hard Part (OCR and Sync)

The challenge: Extract text from PDFs/images, parse certificate numbers and expiration dates, sync tax-exempt status to Shopify customer records.

What broke: Error recovery — AI didn’t handle OCR failures gracefully. Edge cases like blurry scans, multi-page certificates, and expired documents needed manual handling logic.

Time to fix manually: ~3 hours.

Hour 24–48: Polish and App Store Submission

Final deployment: Production-ready, privacy-compliant, App Store approved.

Verdict: AI gets you 90% there. The last 10% is security, compliance, and edge cases that require human judgment.

The Numbers

• AI-generated: ~4,200 lines
• Human-written: ~340 lines (security fixes + compliance + edge cases)
• Time: 48 hours total, ~8 hours of active human intervention
• Result: Approved on Shopify App Store on first submission

Should You Vibe Code Your Next Shopify App?

Yes, if: You’re prototyping or building MVPs. You know Shopify’s platform well enough to catch mistakes. You treat AI as a junior developer, not a replacement.

No, if: You’re submitting to Shopify App Store without security review. You don’t know Shopify’s compliance requirements. You expect zero human intervention.

Try ExemptSync

If you’re a U.S. Shopify merchant dealing with tax exemptions, install ExemptSync from the Shopify App Store.

• Free plan: 10 certificates/month
• AI OCR included
• Takes 5 minutes to set up

Built with 70% AI, 30% human paranoia about security.

Questions about the build process? Drop them below — happy to share what worked and what didn’t.