SDK Reference

Use this skill for language-specific SDK details. Use iii-core-primitives for the common model and iii-error-handling for exception handling.

Install

# TypeScript / Node.js
npm install iii-sdk

# Browser apps
npm install iii-browser-sdk

# Python
pip install iii-sdk

# Rust
cargo add iii-sdk

Choose the SDK

Logger/OpenTelemetry, HTTP request/response types, stream, queue, and worker-connection types live in the helpers package — @iii-dev/helpers (Node, with submodules like /observability and /http) or iii-helpers (Python iii_helpers.*, Rust iii_helpers::*) — installed alongside the SDK.

Common API Map

Node.js

import { registerWorker } from "iii-sdk";
import { Logger } from "@iii-dev/helpers/observability";

const iii = registerWorker("ws://localhost:49134", {
  workerName: "node-worker",
  invocationTimeoutMs: 30000,
});

iii.registerFunction("users::lookup", async (input) => {
  new Logger().info("looking up user", { userId: input.userId });
  return { userId: input.userId, name: "Ada" };
});

Node supports custom WebSocket headers, Logger, OpenTelemetry options, HTTP-invoked function registration, trigger metadata, channels, and custom trigger types.

Browser

import { registerWorker, TriggerAction } from "iii-browser-sdk";

const iii = registerWorker("wss://api.example.com/worker?token=session-token");

const result = await iii.trigger({
  function_id: "backend::get-user",
  payload: { userId: "123" },
});

await iii.trigger({
  function_id: "analytics::track",
  payload: { event: "page_view" },
  action: TriggerAction.Void(),
});

Do not expose the private engine worker port to untrusted browsers; put the rbac-proxy worker in front of it (iii trigger compose::add worker=rbac-proxy). Browser workers cannot send custom WebSocket headers and must not hold backend secrets.

Python

from iii import InitOptions, register_worker
from iii_helpers.observability import Logger

iii = register_worker(
    address="ws://localhost:49134",
    options=InitOptions(worker_name="python-worker"),
)

def lookup_user(data):
    Logger().info("looking up user", {"userId": data["userId"]})
    return {"userId": data["userId"], "name": "Ada"}

iii.register_function("users::lookup", lookup_user)

Python handlers may be sync or async. Use await iii.trigger_async(request) inside async handlers, and iii.trigger(request) in sync contexts. HttpResponse (from iii_helpers.http) uses status_code, like the other helpers packages.

Rust

use iii_sdk::{register_worker, InitOptions, RegisterFunction};
use serde_json::json;

let iii = register_worker("ws://127.0.0.1:49134", InitOptions::default());

iii.register_function(
    "users::lookup",
    RegisterFunction::new(|input: serde_json::Value| -> Result<serde_json::Value, iii_sdk::Error> {
        Ok(json!({ "userId": input["userId"], "name": "Ada" }))
    }).description("Look up a user"),
);

Rust supports typed handlers and schema extraction when input/output types derive schemars::JsonSchema. Add the otel feature when using OpenTelemetry helpers.

Channels

• Use channels for binary data, large payloads, or streaming transfer between workers.
• Pass readerRef or writerRef through a function payload.
• Reconstruct readers/writers from refs in consumers when the SDK requires it.

Namespaces

A worker belongs to one namespace: options.namespace (InitOptions.namespace) → the III_NAMESPACE environment variable → the engine's default. Compose sets III_NAMESPACE to its daemon's namespace (iii compose -n dev ...) for every worker it starts, so a whole project lands in one namespace without any code change. Routing is strict: a function is only reachable in the namespace it registered in.

• iii.trigger({ function_id }) resolves in the calling worker's namespace. Calls to your own functions and to other workers declared in the same worker-compose.yaml need no namespace.
• Engine-owned functions register in default: engine::*, configuration::*, and stream::* (from iii-stream). engine::* resolves there implicitly; for the others pass namespace: "default" on the call when your worker runs in a Compose namespace.
• registerTrigger binds in the worker's namespace. Leave trigger_namespace unset; the engine looks for the trigger type's provider in your namespace first and the engine's own second, which is what lets a project ship its own http provider or fall back to the engine's cron.
• Never prefix a function id with a namespace. The id stays orders::validate; the namespace is a separate field.
• From the CLI, iii trigger -n dev orders::validate ... selects the namespace; omitting -n resolves in default.

// Same-project worker: no namespace
await iii.trigger({ function_id: "orders::validate", payload: order });

// Engine-owned configuration worker from a namespaced project
const cfg = await iii.trigger({
  function_id: "configuration::get",
  namespace: "default",
  payload: { id: "orders" },
});

cfg = await iii.trigger_async(
    {"function_id": "configuration::get", "namespace": "default", "payload": {"id": "orders"}}
)

let cfg = iii.trigger(TriggerRequest {
    function_id: "configuration::get".into(),
    namespace: Some("default".into()),
    payload: json!({ "id": "orders" }),
    ..Default::default()
}).await?;

When to Use

• Use this skill for package names, SDK exports, initialization options, browser security constraints, channel API details, and language-specific syntax.
• Use this when a task asks for Python or Rust examples and the issue is SDK syntax rather than iii architecture.

Boundaries

• For the common Function/Trigger/Worker model, built-in trigger schemas, custom triggers, and invocation mode decisions, use iii-core-primitives.
• For deployment config, engine-owned workers, RBAC (rbac-proxy), and ports, use iii-engine-config.
• For retryability and exception classes, use iii-error-handling.