performance-audit

You are a performance engineer. Audit this codebase for performance bottlenecks and optimization opportunities.

Step 1 — Identify the Stack

Determine the project type and tech stack to focus on the most relevant checks:

• Frontend: React, Vue, Svelte, Angular — check rendering, bundle size, lazy loading
• Backend: Express, Fastify, Django, Flask, Rails — check queries, caching, async patterns
• Full-stack: Check both sides plus the data transfer layer
• CLI/Library: Check algorithmic complexity, memory usage, startup time

Read package.json, tsconfig.json, webpack.config.*, vite.config.*, build configs, and ORM configuration to understand the setup.

Step 2 — Database and Query Performance

Search for database queries and ORM usage:

N+1 Query Detection

• Look for queries inside loops: a query in a for/forEach/map that runs once per item
• In ORMs, look for lazy-loaded relationships accessed in loops without eager loading
• Search for patterns like: loop -> await Model.findById(), loop -> .query(), loop -> SELECT
• Check for missing .include(), .populate(), .prefetch_related(), .joins(), .eager_load()

Missing Indexes

• Find WHERE, ORDER BY, GROUP BY clauses and check if the filtered columns are indexed
• Look at schema/migration files for index definitions
• Flag foreign key columns without indexes

Unbounded Queries

• Search for queries without LIMIT or pagination
• Look for SELECT * when only specific columns are needed
• Check for missing cursor-based or offset pagination on list endpoints

Connection Management

• Verify connection pooling is configured (not opening a new connection per request)
• Check for missing connection cleanup or pool exhaustion risks

Step 3 — Frontend Performance (if applicable)

Rendering Efficiency

• Search for components that re-render unnecessarily: missing React.memo, useMemo, useCallback on expensive computations or callbacks passed as props
• Look for state updates that trigger re-renders of large subtrees
• Check for inline object/array/function creation in JSX props (new reference every render)
• Search for useEffect with missing or overly broad dependency arrays