Local-first.
Capability-routed.

The public interface is not coupled to any one read API. Domain data is canonical, adapter behavior is explicit, and the selected write route is pinned before submission.

The system at a glance

Client-independent inputAny interface or service consumer

Application servicesQueries, commands, workers

Canonical domainFIDs, casts, follows, normalized state

↓ Local-first state + capability dispatch

Persistence portCanonical entities, cursors, feeds and outbox

Capability routerRegistry, consent, access, health, policy

Sync / reconciliationCursors, bounded reads, per-route writes

Adapter boundary

Raw SnapchainFID-scoped protocol reads; follow graph

Indexed social APISearch, aggregate feeds, enriched counters

Validator / writerSigned submits + reconciliation

The diagram separates what is stored, which capability is required and who can fulfill that capability. It is not a claim that every listed optional capability is deployed today.

Read path (local-first)

1. UI requestsFeed, cast, profile or social list

2. Local snapshotImmediate known data without HTTP wait

3. Return snapshotCached data can be read while offline

4. Async refreshBounded pool, provider policy

5. Normalize + persistProvider response → canonical model

6. Publish data changeStable IDs and subscription event

Only cached content survives offline; unseen remote casts cannot appear without a network source. A cache is not an alternative full network replica.

Write path (signer-bound and durable)

Compose intentCast / follow / reaction

Sign locallyAuthorized app key, never a provider secret

Durable outboxCanonical signed message hash

Bind onceWrite-provider ID + exact endpoint identity

Validator submitSigned protocol message

ReconcileReader observes canonical hash/state

Why route pinning is non-negotiable

Changing the preferred node after composing a message must not make an unresolved write silently jump to another validator. Genycaster persists the writer association before its HTTP transmission, with a fail-closed path when provenance is missing.

Five capability origins

Class	Examples	Availability
Protocol	FID, casts, links, signer state	Raw reader where supported
Derived	Global Explorer, search, rankings, counts	Indexer or bounded local derivation
Compatibility	Managed app-specific APIs	Optional and explicit
Extension	Independent app functionality	Feature-gated
Local	Cached search, drafts, settings, outbox	Device-side

Read the actual implementation

Start with the repository's architecture overview, routing consent policy and durable writer contracts.