Beginner LevelSystem Design & Architecture
What is Rate Limiting and how does it protect backend servers from traffic surges?
❓ Interview Prompt: Explain Rate Limiting, HTTP 429 Too Many Requests, protecting against DoS attacks, Token Bucket algorithm, and client throttling.
Rate Limiting caps the maximum number of requests a client IP or authenticated user can submit within a specified time window:
Why Rate Limiting is Mandatory:
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Prevents Denial of Service (DoS) attacks and web scraping.
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Protects downstream databases from being overwhelmed during traffic spikes.
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Returns standard '429 Too Many Requests' HTTP status code with 'Retry-After' response headers.
Code Implementation Example
typescript
// Rate limiting header response format
res.setHeader('X-RateLimit-Limit', '100');
res.setHeader('X-RateLimit-Remaining', '0');
res.setHeader('Retry-After', '60');
res.status(429).json({ error: 'Rate limit exceeded. Try again in 60 seconds.' });💡Returning HTTP 429 Rate Limit Exceeded headers.
🎯 Interview Key Takeaway
Enforce rate limiting on all public API endpoints to protect backend infrastructure from DoS and traffic spikes.
#System Design#Rate Limiting#Throttling#HTTP 429#Beginner
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