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LAB REPOSITORYPRO CODEBASE

Load Balancer From Scratch

A tiny L7 request router with health checks, round-robin routing, least-connections routing, and forwarded request metadata.

JavaScriptDifficulty: starter
$node implementations/load-balancer-from-scratch/src/demo.js
Key Takeaways & Architecture Lessons
  • 01.A balancer is a small policy engine around a backend pool.
  • 02.Health state is checked before routing, not after the request already failed.
  • 03.Production versions add sockets, retries, draining, and observability around the same core choice.

Protected Implementation File

Full source code for README.md is included in the Pro engineering package.

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