AI Code Reviewer

A full-stack AI-powered code review application using React (Vite), Express.js, and Google Gemini API.

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Project Structure

code-reviewer/
│
├── Backend/
│   ├── src/
│       ├── routes
│           ├── ai.routes.js
│       ├── controllers
│           ├── ai.controlles.js
│       ├── services
│           ├── ai.service.js
│   ├── server.js
│   ├── package.json
│   └── .env
│
└── Frontend/
    ├── src/
        ├── components
    ├── App.jsx
    ├── package.json

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Backend Setup (Express + Gemini)

1️⃣ Navigate to Backend

cd Backend

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2️⃣ Install Dependencies

npm install express cors dotenv nodemon @google/generative-ai

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3️⃣ Environment Variables

Create a .env file:

GOOGLE_GEMINI_KEY=your_api_key_here

⚠ Important: No spaces around =

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4️⃣ Start Backend Server

nodemon server.js

Server runs at:

http://localhost:3000

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Frontend Setup (React + Vite)

1️⃣ Navigate to Frontend

cd Frontend

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2️⃣ Install Dependencies

If ESLint conflicts occur (recommended safe command):

npm install react-simple-code-editor prismjs react-markdown rehype-highlight highlight.js axios --legacy-peer-deps

Standard install (if no conflicts):

npm install react-simple-code-editor prismjs react-markdown rehype-highlight highlight.js axios

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3️⃣ Start Frontend

npm run dev

App runs at:

http://localhost:5173

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API Endpoint

Review Code

POST

http://localhost:3000/ai/get-review

Body:

{
  "code": "your code here"
}

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Common Error Fixes

🔴 MODULE_NOT_FOUND

npm install

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🔴 ESLint / Peer Dependency Conflict

npm install --legacy-peer-deps

OR downgrade ESLint:

npm install eslint@9 --save-dev

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🔴 Gemini API 429 Error (Quota Exceeded)

Cause:

• Free tier request limit reached

Fix:

• Wait for quota reset OR enable billing

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🔴 500 Internal Server Error

Check backend terminal logs:

nodemon server.js

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Best Practices

✔ Never commit .env file ✔ Use environment variables for API keys ✔ Add proper error handling ✔ Avoid using index as React key

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Tech Stack

Frontend: React + Vite + PrismJS + Markdown

Backend: Express.js + Gemini API

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Run Full Application

Terminal 1 → Backend

cd Backend
nodemon server.js

Terminal 2 → Frontend

cd Frontend
npm run dev

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License

For learning and educational purposes.