Hey,

let me show you how I built Cal AI - an AI app that analyzes photos of your meals and instantly tells you the estimated macros. (calories, fats etc)
No coding. No “dev team.”

Here’s the breakdown:

Step 1: Head over to replit.com

Step 2: Type this exact prompt into the chat

Build a mobile-first web app that works as a calorie tracker.

Core features:

• User uploads a picture of a meal

• Use OpenAI GPT-4o API to analyze the image and identify the food

• Estimate macros count

• Show the image + estimated calories below

• Option to upload another photo

Requirements:

• Super clean, minimal UI (like Apple Health or Notion mobile)

• Must be mobile-optimized and responsive

• No extra features like login, history, or macros — just image → macro result

• Use React for the frontend and Flask or FastAPI for the backend

• Style with Tailwind or clean custom CSS

• The final result should look like a polished micro SaaS MVP

Step 3: Watch it build the app for you

The AI agent will start coding the app right in front of you. You don’t need to touch anything yet, just let it do his thing.

Step 4: Get your OpenAI API Key

You need the OpenAI key to analyze images. Go to platform.openai.com and generate your API key and paste it into Replit.

Step 5: Upload a food image

Once the app is running, upload an image of a meal - it could be anything. The app uses OpenAI’s 4o API to analyze the images and provide all macros.

Final Result

We just rebuilt Cal AI in a few minutes… without writing any code. You can now tweak it even more, add more features, or even turn it into a full health tracking product.

I hope you enjoyed this short tutorial. You don’t need to “learn to code” to build with AI.

You just need a good idea that you can execute on ASAP. Then start recording videos showcasing it on TikTok, YT, and IG, start driving traffic to it and print money.

Start building. Ship fast. Use AI to your advantage.

—— Isaac Mihai