Open sourceEvery system on the site is one JSON file anyone can add.
See how real systems handle real traffic.
Pick a system, press Play, and watch a request travel through it and back, hop by hop. Click any part to see what it does and how sure we are about it.
going outcoming backEvery system page works like this: each hop shows what is sent, and the flow ends when the answer is back with the user.
Boxes and arrows, but you can poke them.
Static diagrams show the parts. HowItScales shows how a request moves through them, and what happens when too many arrive.
- 01Click any componentSee what it does, what it talks to, and whether that's documented, an assumption or hypothetical.
- 02Follow a request out and backWatch what each component sends and what comes back, with a plain-English note for every hop.
- 03Push the traffic coming soonRaise the requests per second and watch queues fill, autoscaling kick in, and requests get rejected.
Systems
UberMobility
Live driver locations, matching through a geospatial index, and surge pricing.
4 guided flows#ride-hailing#geospatial#real-time
URL ShortenerWeb basics
Turns long links into short ones and redirects fast, with a cache in front of the database.
2 guided flowsLoad data#caching#read-heavy#classic
Know how a system works? Describe it in one file.
No code to write. CI checks your file, a maintainer reviews it, and it goes live with your name on it.
- Copy
systems/_template.json - Run
yarn validateto check it - Open a pull request
{
"schemaVersion": 1,
"id": "url-shortener",
"title": "URL Shortener",
"nodes": [
{ "id": "browser", "label": "Browser", "kind": "client" },
{ "id": "redirect", "label": "Redirect service",
"kind": "service" }
],
"edges": [
{ "id": "browser-redirect",
"from": "browser", "to": "redirect" }
]
}