The valley of webhooks
Webhooks are a poor replication protocol: they are unordered, at-least-once notifications, so every consumer rebuilds ordering, deduplication, bootstrap, retries, and reconciliation around a stream that can silently lose deletes. Weli proposes SCROLL (Synchronized Change Replication Over Line Logs): a provider-served, cursor-addressed log of full-state events that supports both resumable polling and a long-lived GET stream.
With one feed, bootstrap and live sync share a code path, tombstones make deletes explicit, replays are harmless upserts, and a checkpoint count/checksum can verify the local replica. Hacker News commenters connected the design to Braid-HTTP Subscriptions and Svix’s FIFO/polling/streaming products, while noting the hard parts are adoption, provider sequencing, and the extra lag or traffic of polling.