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CodeSpy breaks down system design, Spring AI, and distributed systems the way we wish someone had explained them to us — with real diagrams, real code, and no shortcuts.

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RateLimiter.java

01// Sliding-window limiter, Redis-backed
02@Service
03public class RateLimiter {
04  private final RedisTemplate redis;
05
06  public boolean allow(String key) {
07    long count = redis.increment(key);
08    if (count == 1) redis.expire(key, 60);
09    return count <= 100;
10  }
11}

✓ Explained in Payment Processing Systems

21+Guides & tutorials

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01

Real systems, not toy examples

Every architecture is one you could actually ship — with the trade-offs left in.

02

Interview-ready structure

Requirements → estimation → design → deep dive, the way you’d walk an interviewer through it.

03

Code you can actually run

Spring Boot, Redis, Docker — snippets are tested, not decorative.

Who’s behind this

Two engineers, writing what we wish we’d had.

PP

Prashant Pandey

Founder & Editor-in-Chief

Leads editorial strategy, Spring AI, and distributed-systems content — obsessed with explaining hard things simply.

AB

Ashmita Basu

Co-founder & Content Creator

Leads system design coverage — turning whiteboard-scale problems into guides anyone can follow.