PurpleSky, an ATProto PDS built on Farcaster

Field notes

PurpleSky separates the visible ATProto service from its proposed storage and ordering substrate: Farcaster supplies shared state, while ATProto clients continue to see a conventional PDS. The architecture assigns a stable service identity to a DID document and treats nodes as interchangeable gateways rather than permanent account homes. The page also names local databases, indexes, MSTs, and CAR caches as reconstructable materialized state, while acknowledging that admission, finality, retention, and recovery still require proof.