Five services at 99.9% give you 99.5%

transcript

Every service in your order flow is 99 point 9 percent available. Great. Chain five of them, and your checkout is worse than any one of them.

A user places an order. The API calls inventory. Which calls payment. Then shipping. Then email. And the user waits for every single one. If any step fails, the whole order fails.

One service takes 200 milliseconds. Chain five: the user waits a full second. Latencies add. And availability multiplies. Five at 99 point 9 percent gives about 99 point 5. Every hop costs you.

Now flip it. The API writes the order to a queue. And replies at once: order created. About 50 milliseconds. The work didn't disappear. It just left the user's critical path.

Behind the queue, each service picks up orders at its own pace. Email slow today? It catches up later. The order was already accepted.

But here's the catch. Now the queue has to be reliable. Never lose a message. Survive producers that outrun consumers. That's the whole week.

A synchronous chain is only as good as all its links multiplied. Stop waiting. Queue the work.

Full breakdown in the lecture.