Memo Observability Pipeline — Beacon to Owner Surfaces Diagram

Read derive surface

Beacon batches 10 event types; the API validates JWT plus rate limits
page_leave finalises the visit row and emits per-visit signals inline
Cross-visit signals need 72h of context, so a cron derives them idempotently
Owner reads Postgres live plus Mongo event history (second store, in cards)

Contracts

Slug travels in meta tags and request bodies, never parsed from URLs
visit_signals upserts are idempotent on (visit_id, kind)
Reserved event types stay unenforced until a producer ships