> For the complete documentation index, see [llms.txt](https://faisalaffan.gitbook.io/design-system/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://faisalaffan.gitbook.io/design-system/readme.md).
# README
Go monorepo implementing all 12 system design problems from Alex Xu's *System Design Interview* (2nd Ed), backed by theory from Kleppmann's *Designing Data-Intensive Applications*.
**100 tests | 44 packages | 12 services | 2 shared packages**
## What's Inside
| # | Service | Port | Core Pattern |
| -- | ------------------- | ---- | ----------------------------- |
| 1 | url-shortener | 8080 | Base62 + collision retry |
| 2 | rate-limiter | 8081 | Sliding window + token bucket |
| 3 | chat-system | 8082 | WebSocket rooms + broadcast |
| 4 | notification-system | 8083 | Pub/sub + multi-channel |
| 5 | unique-id-generator | 8084 | Snowflake 64-bit |
| 6 | key-value-store | 8085 | Consistent hashing sharding |
| 7 | search-autocomplete | 8086 | Trie + top-K frequency |
| 8 | news-feed | 8087 | Fan-out on write |
| 9 | web-crawler | 8088 | BFS + politeness + dedup |
| 10 | youtube | 8089 | Metadata + search + transcode |
| 11 | google-drive | 8090 | Files + folders + versioning |
## Quick Start
```bash
go run ./services/url-shortener # Pick any service
go test ./... # 100 tests
go build ./... # Build all
```
---
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