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Cost Engineering

Two architectures, same traffic, 8× different bill.

compute costdatabase coststorage costegressLLM API costunit economics

Lessons

  1. 19.1The cloud cost model: what you actually pay forA cloud bill isn't just "the servers". It's many meters ticking at once. Here's what each one counts, and the question to always ask. 30 min Trade-off matrix
  2. 19.2Two architectures, same traffic, 30× the billTwo designs can serve the same traffic, one at about €6,000 a month and one at €48,000. Neither is wrong. Here's how to choose. 30 min Scale journey Trade-off matrix
  3. 19.3LLM API costs: tokens × price, and the levers that cut it 10×AI features are billed by the word, in and out. Learn where the money goes and the levers that can cut the bill around ten times. 30 min AI cost simulator

On the job: try it on your own project

Get your last cloud and API bills, or ask someone who has them. Ask Claude Code to help you group the spend by service and match each line to a feature. Then compute one unit cost, such as cost per active user or cost per order. Write a one-page cost breakdown with the top three cost drivers and one saving worth trying.

Can you do this now?

0/4. Anything you can't tick yet: reopen that lesson's practice ladder.