#1473
Documentation Request: Relay Selection & Delivery Semantics for External Geohash Publishers
Three things affecting external tools that publish kind-20000 events to a geohash channel:
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Geohash channels subscribe to relays chosen by proximity to the geohash (from the ~300-relay directory). A publisher using a fixed relay set may never reach the client; the geo-selection has to be replicated to target a cell.
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Sparse or ocean geohash cells map to few or unreachable nearby relays, but the channel still displays normally. No signal that the cell is effectively undeliverable.
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kind-20000 ephemerality means a client subscribing a few minutes late cannot retrieve a recent message. Expected by design, but a delivery limitation.
All three observations verified correct: relay selection is nearest-5 by haversine distance from the bundled directory (
GeoRelayDirectory.closestRelays), sparse cells degrade silently, and kind-20000 ephemerality means no backfill — so an external publisher on a fixed relay set can miss clients entirely. Keeping this open as a docs task. It will most likely land as the Nostr-bridge/relay-selection chapter of the protocol spec proposed in #1448, which would give external publishers a stable contract to target; the custom-relay support that just merged (#1486) helps people, not publishers, so your ask stands.