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Explain advanced API gateway rate limiting and distributed quota enforcement systems.

Updated May 24, 2026

Short answer

Rate limiting controls request frequency using distributed counters and token-based algorithms to protect system stability.

Deep explanation

Rate limiting prevents abuse and ensures fair resource usage.

Algorithms:

  1. Token bucket

Tokens refill over time.

  1. Leaky bucket

Smooths traffic flow.

  1. Fixed window counter

Simple but burst-prone.

  1. Sliding window log

Accurate but expensive.

  1. Sliding window counter

Approximation of log method.

Distributed enforcement:

  • Redis counters
  • consistent hashing of users
  • global quota coordination

Challenges:

  • clock synchronization
  • distributed counter consistency
  • burst handling
  • fairness across regions…

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