state

The state worker is a server-side key/value store. Values are addressed by a scope (namespace) and a key, shared across every worker connected to the engine, and persisted through a pluggable adapter (kv or redis). Callers reach the store through six state::* functions invoked with iii.trigger({ function_id: 'state::...', payload }). Install it with iii worker add state; it replaces the engine's built-in iii-state worker, which must be removed from the engine config first.

State does not push updates to SDK clients. Reactivity is delivered by a state trigger type that fires state:created, state:updated, or state:deleted after every successful mutation, so downstream functions can react to data changes without polling. The kv adapter (default) supports in_memory or file_based persistence; redis proxies to a Redis backend. The function surface is identical across adapters.

When to Use

• Two or more functions need shared state without standing up a separate database.
• A counter or per-entity document needs atomic partial updates instead of read-modify-write.
• A write in one function should trigger side effects elsewhere (cache invalidation, audit logs, notifications, projections).
• You want a specific scope/key watched and reacted to only when that slot changes.

Boundaries