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.

Frequently Asked Questions

Can AI build a complete Shopify app by itself?

AI can accelerate scaffolding, boilerplate, and implementation ideas, but a production Shopify app still needs developer review, security checks, billing logic, merchant UX decisions, and App Store compliance work.

What parts of ExemptSync were best suited for AI assistance?

AI was most useful for repetitive code, edge-case brainstorming, copy drafts, schema design, and test-case generation. The final architecture and product judgment still needed human ownership.

Is vibe coding safe for Shopify apps?

It can be safe only with strict review. You need to inspect generated code, verify API scopes, test billing and webhook paths, and avoid shipping code you cannot explain.

What should developers learn from this experiment?

AI is strongest when paired with a developer who knows the platform. The leverage comes from faster iteration, not from skipping architecture, QA, or merchant empathy.