Part 4: Logic-First - Building Complex Features with AI

"It Works > It Looks Good"

If you are building a tool that processes data, handles complex calculations, or manages user workflows, starting with a pretty UI might be a distraction.

This is the Logic-First approach. It is favored by engineers, but accessible to everyone thanks to modern AI models like Claude 3.5 Sonnet and GPT-4o.

The Brain: LLMs as Architects

When logic is the priority, you need a model that can "think" deeply.

Tool of Choice: Claude Projects (Anthropic)

Claude Projects allows you to upload "Project Knowledge"—your requirements documents, database schemas, and API documentation. This context window is massive compared to standard chats.

The Workflow

1. The Spec Sheet (The most important step)

Before writing code, write English. Create a text file called spec.md:

• Data Structure: "A User has a name, email, and subscription_tier. A Job has a title, description, and status."
• Rules: "A User on the 'Free' tier can only post 1 Job per month."
• Flow: "When a User posts a Job, email the Admin and deduct 1 credit."

2. Generate the "Backend" Logic

Ask Claude/GPT to write the functions without the UI initially.

"Read my spec.md. Write a TypeScript function that handles the Job Posting logic. Include all validation checks for the Free tier limit."

3. Test the Logic

Ask the AI to generate a test case.

"Now simulate a user trying to post a 2nd job. detailed the output." Did it fail as expected? Good.

4. Snap on the UI

Only after the logic is solid do you ask the AI to build the interface.

"Now build a React form component that connects to this postJob function. Handle the error states (e.g., if the user is out of credits, show a red alert)."

The "Last Mile" Problem

You've built the logic. You have the UI. You've followed our 4-part series. But now you face the final boss: Production.

• Security: Is your database secure?
• Payments: Is Stripe integrated correctly?
• Deployment: How do you get this off localhost?

This is where ShipTheProduct steps in. We specialize in taking your AI-generated prototypes and turning them into secure, scalable, production-ready businesses.

Ready to launch?

Series Recap

1. Part 1: No-Code (For speed & simplicity)
2. Part 2: Low-Code & AI (For flexibility)
3. Part 3: Design-First (For visual apps)
4. Part 4: Logic-First (You are here)