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Code Reviewer — Security, Performance & Best Practices

Get thorough code reviews covering bugs, security vulnerabilities, performance bottlenecks, and clean refactoring.

@promptallFeb 25, 2026 6086

Act as a senior engineer with 10+ years experience. Review this code:

```
[PASTE YOUR CODE HERE]
```
**Language/Framework:** [SPECIFY]

Analyze and provide:

### 1. Bugs & Logic Errors
List each with line number and fix

### 2. Security Vulnerabilities
Check for: SQL injection, XSS, auth bypass, insecure deserialization, IDOR, exposed secrets

### 3. Performance Issues
Check for: N+1 queries, memory leaks, blocking I/O, unnecessary re-renders, missing memoization

### 4. Code Quality
- Naming conventions
- Single responsibility violations
- DRY violations
- SOLID principles
- Cyclomatic complexity

### 5. Refactored Version
Improved code for the most critical section with explanation

Format each issue:
**Issue:** [description]
**Severity:** 🔴 Critical / 🟠 High / 🟡 Medium / 🟢 Low
**Fix:** [specific solution with code example]

Result Text

## Code Review — Node.js Express Auth API **Issue 1: SQL Injection** 🔴 Critical | Line 23: `db.query("SELECT * FROM users WHERE id = " + req.params.id)` Fix: `db.query("SELECT * FROM users WHERE id = $1", [req.params.id])` **Issue 2: Missing Rate Limiting on /login** 🟠 High | Brute force attack vector Fix: Add express-rate-limit: max 10 requests per 15 min per IP **Issue 3: JWT Secret in Code** 🔴 Critical | Line 5: `const secret = "mysecret123"` Fix: `const secret = process.env.JWT_SECRET` — rotate secret immediately **Issue 4: Synchronous File Read** 🟡 Medium | Line 45: `fs.readFileSync('./config.json')` Fix: `await fs.promises.readFile('./config.json')` **Refactored Auth Middleware:** ```js const authenticate = async (req, res, next) => { try { const token = req.headers.authorization?.split(' ')[1]; if (!token) return res.status(401).json({ error: 'Unauthorized' }); req.user = await verifyToken(token); next(); } catch { res.status(401).json({ error: 'Invalid token' }); } }; ```