iii

Schema-validated, reactive registry for named configuration entries — the runtime configuration surface used by engine and Compose workers.

How iii works and the iii-sdk surface for authoring workers, triggers, and functions. Teaches the ordered way to gain a capability before writing code — (1) check functions already registered in the engine, (2) search the public registry via iii-directory, (3) build a worker. Single self-contained skill — meant for system-prompt injection; do not re-fetch.

Use when composing iii primitives into backend architectures: durable workflows, reactive backends, observer side effects, agentic pipelines, event-driven CQRS, effect pipelines, and trigger-transform-action automation.

Use when registering iii functions, binding triggers, observing functions, selecting sync/void/enqueue invocation, creating workers, inspecting the live worker registry, installing registry workers, authoring event sources, moving channel data, or adapting external HTTP functions across TypeScript, Python, and Rust.

Configure a managed iii engine through worker-compose.yaml or a directly supervised engine through config.yaml. Use for engine ports, RBAC via the rbac-proxy worker, observer limits, streams, sandboxes, and configuration storage.

Handle iii engine and SDK errors across Node, Python, Rust, and browser workers. Use when interpreting error codes, retryability, RBAC denial, timeouts, handler failures, or SDK-specific exception surfaces.

Install the iii engine, set up your first worker, and get a working backend running. Use when a user wants to start a new iii project, install the SDK, or needs help with initial setup and configuration.

OpenTelemetry-backed tracing, structured logs, metrics with rollups, alerts, sampling, and baggage for the engine — emit and query telemetry through `engine::*` functions and react to logs with a `log` trigger.

Use when observing iii functions with iii.observe, writing filters, reacting to engine events, writing observable functions with owner delivery (onObserverAdded, obs.emit, obs.call), tuning local dispatch, or migrating from the deprecated registerTrigger / registerTriggerType across TypeScript, browser, Python, Rust, and Go.

Ephemeral microVM sandboxes for running untrusted or agent-generated code in isolation — a one-call run path, a create/exec/stop lifecycle, and a set of filesystem operations.

Use when working with iii SDK APIs across Node.js, browser, Python, Rust, or Go: package installation, worker initialization, function/trigger registration, observers, invocation, local dispatch, channels, logging, OpenTelemetry, and language-specific caveats.

Durable real-time streams with a CRUD function surface plus reactive triggers that fire on item changes and WebSocket subscriber lifecycle — reach for it to build live backends without polling. iii-stream is deprecated (iii-stream) and will be removed in an upcoming release. Behavior is unchanged for now. Migration guide: https://iii.dev/docs/upgrading/migrate-from-streams

WebSocket listener that SDK workers connect to. Use to expose the engine to trusted (internal) and untrusted (RBAC-protected) workers, gate function and trigger registration, and audit or transform every invocation through a middleware function. Mounts channel WebSocket endpoints on every listener.

Turn a tech-spec directory into an interactive, marketing-grade web presentation — built so engineers understand the design, the reader is convinced of the why, and the result is shareable in public. Use when someone wants a spec turned into a deck.