⬡ SPOC · ARCHITECTURE & REQUEST PATH

flowchart LR
  U[Client / agent] -->|GET page| CDN[(Vercel CDN · static index, cities.json, gyst.js)]
  U -->|POST /api/flow · ≤256 UUIDs| F[Vercel Function · Node, 128 MB, 5 s max · runs on AWS Lambda]
  F --> D[PARSE: decode 128 bits]
  D --> R{namespace?}
  R -->|this city| A[accepted]
  R -->|other city| W[forwarded: reply names spoc.city]
  R -->|unknown| H[forwarded: hub aggregator]
  D -->|bad bits| B[blocked]
  A & W & H & B --> RC[SHA-256 receipt chain]
  RC -->|JSON response| U
  F -.->|one log line per request| L[(Vercel Runtime Logs / Observability)]

Why it can't get chatty

rule	how
no outbound calls	a SPOC never calls another SPOC; forwarding is a field in the reply
no background work	no cron, queues, polling, heartbeats or LLM calls; nothing runs unless a request arrives
bounded work	≤256 UUIDs and ≤32 KB per request, 128 MB, 5 s max; pure bit math (~µs per UUID)
cache first	pages and cities.json are static; /api/spoc is CDN-cached for a day
observable	each /api/flow logs `{evt:"spoc.flow", spoc, n, counts, conserved, head, ms}`; filter Runtime Logs on `spoc.flow`

Endpoints

host	role
spoc.austinsays.com · spoc.sonomasays.com · spoc.newyorksays.com · spoc.londonsays.com · spoc.tokyosays.com	SPOC_ENDPOINT 0x1F0
says-spoc.vercel.app (any other host)	Hub Aggregator view, SPOC_AGGREGATOR 0x1F1

← SPOC