simulations

The library

Everything written here, in one place. A topic is a broad collection of parts; a part collects articles; an article is one thing explained, on its own. Open a topic to explore its maps, or jump straight to any article below.

The life of a request25 items

From the moment a request leaves the browser to the moment the response lands: name resolution, the handshakes, the edge, the front door, the cluster, the work, and the way home. Click any box with a ＋ to go deeper.

  1. Finding the addresspart
  2. The caches before the questionarticle
  3. The resolver's climbpart
  4. One IP, many machinesarticle
  5. When the answer is a detourarticle
  6. Opening the pipepart
  7. Three packets before helloarticle
  8. Proving who you are talking topart
  9. The chain of signaturesarticle2 pages
  10. Skipping the ceremonyarticle
  11. The edge takes it firstpart
  12. The bouncer at the doorarticle
  13. Answering from the shelfarticle
  14. The origin's front doorpart
  15. Spreading without addingarticle
  16. The gateway's checklistarticle
  17. Inside the clusterpart
  18. The network you pretend is yoursarticle
  19. From balancer to podpart
  20. The pod's own wirearticle
  21. Services talking to servicesarticle
  22. Leaving the buildingarticle
  23. The work itselfarticle
  24. The response's way homearticle
Keeping the line open9 items

Request/response ends the conversation on purpose. Everything here — polling, long-polling, SSE, WebSockets, gRPC streams, QUIC, webhooks — is a different answer to one question: how does the server speak when it has something to say?

  1. Asking again, and againarticle
  2. Asking, then waitingarticle
  3. Server-sent eventsarticle
  4. WebSocketspart
  5. A million open mouthsarticle
  6. HTTP/2 and gRPC streamsarticle
  7. QUIC and HTTP/3article
  8. Webhooksarticle
Nudges, at scaledeepdive21 items

The system behind every tooltip, push and "come back": targeting, delivery, templating, measurement — derived from first principles, every approach followed to where it breaks, from one user to a hundred million.

  1. What a nudge even ispart
  2. The anatomyarticle
  3. Requirements, in phasesarticle4 pages
  4. The landscapearticle
  5. Who gets itpart
  6. Segmentsarticle
  7. Resolutionarticle
  8. The arbiterarticle
  9. How it reaches thempart
  10. The fan-outarticle
  11. The channelsarticle
  12. The live patharticle
  13. What it says, on screenpart
  14. Templatingarticle
  15. UI logic, CTAs, and the screen you do not ownarticle
  16. Did it workpart
  17. Event collectionarticle
  18. Aggregationarticle
  19. Experimentsarticle
  20. What you can never have all ofarticle