From "hello" to "online at scale."
This is a Handbook entry — the practitioner's companion. Where the Guides explain the machine, the Handbook is concerned with judgement: what to choose, when, and why. The full write-up will migrate here from the original build, with the same examples and the same tables, restyled for the new layout.
Why this entry exists
Every Handbook entry answers a question that keeps coming up. For design a realtime chat, the question is the one people ask when the textbook answer is too clean and the internet answer is too noisy — what do people actually do?
How it is structured
You'll find a short framing, a decision matrix, and a handful of worked examples. Where a decision points to a tool or simulator in the Toolkit, the link takes you straight there so you can try the idea under your own conditions.
What to read next
The companion entries in the right rail cover the adjacent ground. If you're new to the topic, start with a Primer and follow up with the matching Deep dive; if you're already working in the space, the Deep dive alone may be the fastest route.