Iii Getting Started

Getting Started with iii

iii replaces your API framework, task queue, cron scheduler, pub/sub, state store, and observability pipeline with a single engine and three primitives: Function, Trigger, Worker.

Step 1: Install the Engine

curl -fsSL https://install.iii.dev/iii/main/install.sh | sh

Verify it installed:

iii --version

Step 2: Create a Project

iii create

Follow the interactive prompts to select a template and language. The default quickstart template includes TypeScript, Python, and Rust workers.

Then change into the project directory you chose at the prompt:

cd <your-project>

Step 3: Start the Engine

iii --config iii-config.yaml

The engine starts and listens for worker connections on ws://localhost:49134. The REST API is available at http://localhost:3111. The console is available at http://localhost:3113.

Step 4: Install the SDK

Pick your language:

# TypeScript / Node.js
npm install iii-sdk @iii-dev/helpers

# Python
pip install iii-sdk iii-helpers

# Rust
cargo add iii-sdk iii-helpers

Step 5: Write Your First Worker

TypeScript

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

const iii = registerWorker(process.env.III_URL ?? "ws://localhost:49134");

iii.registerFunction(
  "hello::greet",
  async (input) => {
    const logger = new Logger();
    const name = input?.name ?? "world";
    logger.info("Greeting user", { name });
    return { message: `Hello, ${name}!` };
  },
  { description: "Greet a user by name" },
);

iii.registerTrigger({
  type: "http",
  function_id: "hello::greet",
  config: { api_path: "/hello", http_method: "POST" },
});

Python

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

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

def greet(data):
    logger = Logger()
    name = data.get("name", "world") if isinstance(data, dict) else "world"
    logger.info("Greeting user", {"name": name})
    return {"message": f"Hello, {name}!"}

iii.register_function("hello::greet", greet, description="Greet a user by name")
iii.register_trigger({"type": "http", "function_id": "hello::greet", "config": {"api_path": "/hello", "http_method": "POST"}})

Rust

use iii_sdk::{register_worker, InitOptions, RegisterFunction};
use iii_sdk::protocol::RegisterTriggerInput;
use iii_helpers::observability::Logger;
use serde_json::json;

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

iii.register_function(
    RegisterFunction::new("hello::greet", |input: serde_json::Value| -> Result<serde_json::Value, String> {
        let logger = Logger::new();
        let name = input["name"].as_str().unwrap_or("world");
        logger.info("Greeting user", Some(json!({ "name": name })));
        Ok(json!({ "message": format!("Hello, {}!", name) }))
    }).description("Greet a user by name"),
);

iii.register_trigger(RegisterTriggerInput {
    trigger_type: "http".into(),
    function_id: "hello::greet".into(),
    config: json!({ "api_path": "/hello", "http_method": "POST" }),
    metadata: None,
})?;

Step 6: Test It

curl -X POST http://localhost:3111/hello \
  -H "Content-Type: application/json" \
  -d '{"name": "iii"}'

Expected response:

{ "message": "Hello, iii!" }

Add Existing Workers

To add a capability that already exists, browse https://workers.iii.dev/ and install the worker by name:

iii worker add iii-state
iii worker add iii-queue
iii worker add image-resize@0.1.2

iii worker add writes project config, installs the worker artifact, starts it, and records the pin in iii.lock when the worker comes from the registry. Commit iii.lock with your config so other machines can replay the same worker set with iii worker sync.

Install Agent Skills

Get all iii skills for your AI coding agent:

npx skills add iii-hq/iii/skills

Skills teach your agent the top-level iii model: functions, triggers, workers, registry access, SDKs, engine configuration, architecture patterns, and error handling. Worker-backed capabilities live with the worker docs and registry entries.

Adapting This Pattern

• Add more functions to the same worker — each gets its own registerFunction + registerTrigger calls
• Use :: separator for function IDs to namespace them: orders::create, orders::validate
• Add cron triggers with { type: 'cron', config: { expression: '0 0 9 * * * *' } } (7-field: sec min hour day month weekday year)
• Add queue triggers with { type: 'durable:subscriber', config: { topic: 'my-queue' } }
• Use iii.trigger() to invoke other functions from within a function
• Use state::get / state::set to persist data across function calls
• Use iii worker add <name> when the capability already exists in the worker registry

Recommended Next Steps

After getting your first worker running:

1. Register functions, triggers, and workers — See iii-core-primitives
2. Choose the right SDK APIs — See iii-sdk-reference
3. Configure the engine — See iii-engine-config
4. Explore backend patterns — See iii-architecture-patterns
5. Handle failures well — See iii-error-handling

Key Resources

• Quickstart Guide
• SDK Reference — Node.js
• SDK Reference — Python
• SDK Reference — Rust
• Engine Configuration
• Console

Pattern Boundaries

• For function and trigger registration patterns, worker creation, worker registry access, trigger payload schemas, invocation modes, channels, custom triggers, and HTTP-invoked functions, prefer iii-core-primitives
• For language-specific SDK APIs, prefer iii-sdk-reference
• For engine configuration, prefer iii-engine-config
• For worker-backed HTTP, cron, queue, pubsub, state, stream, and observability behavior, use the matching worker docs under engine/src/workers/**/skills
• Stay with iii-getting-started for installation, initial setup, and first-worker guidance

When to Use

• Use this skill when the task is about installing iii, creating a new project, or writing a first worker.
• Triggers when the request asks for setup help, quickstart guidance, or getting started with iii.

Boundaries

• Never use this skill as a generic fallback for unrelated tasks.
• You must not apply this skill when a more specific iii skill is a better fit.
• Always verify environment and safety constraints before applying examples from this skill.