iii — Real-Time Service Composition and Observation Framework

Introduction

iii is a framework for composing, extending, and observing services in real-time. Built in Rust with SDKs for JavaScript, Python, and TypeScript, it enables developers to wire together microservices, APIs, and AI components into observable pipelines.

What iii Does

• Composes services into pipelines with real-time data flow visualization
• Provides a unified SDK for JavaScript, Python, and TypeScript
• Offers real-time observation of every request and response in the pipeline
• Supports hot-reloading of service configurations without downtime
• Enables AI agent integration as first-class pipeline components

Architecture Overview

The core runtime is written in Rust for performance and safety. It exposes a service graph where each node is a composable unit (API call, AI model, data transform). SDKs for JS, Python, and TS communicate with the Rust runtime via a lightweight RPC layer. An embedded dashboard provides real-time tracing of requests flowing through the graph.

Self-Hosting & Configuration

• Install the SDK for your language via npm or pip
• Define service compositions in YAML or programmatically via the SDK
• Deploy the Rust runtime as a standalone binary or Docker container
• Configure observability outputs (console, file, or external tracing)
• Set up authentication and rate limiting for exposed endpoints

Key Features

• Rust core for low-latency service composition
• Multi-language SDKs with consistent APIs
• Built-in real-time tracing and observation dashboard
• Hot-reload for service graph changes
• AI model nodes as first-class pipeline components

Comparison with Similar Tools

• Temporal — workflow orchestration; iii is real-time service composition
• Prefect — Python-centric data pipelines; iii is polyglot and service-focused
• Dapr — sidecar-based runtime; iii is an embedded composition framework
• Inngest — event-driven functions; iii is continuous service graph execution

FAQ

Q: Do I need Rust knowledge to use iii? A: No. The JavaScript, Python, and TypeScript SDKs handle all interaction with the Rust core.

Q: Can iii replace my API gateway? A: iii is a composition framework, not a gateway. It works alongside gateways to orchestrate backend services.

Q: How does real-time observation work? A: Every service call in the graph emits structured events that the built-in dashboard or external collectors can consume.

Q: Is iii suitable for production workloads? A: Yes. The Rust core is designed for low-latency production use with configurable resource limits.

Sources

• https://github.com/iii-hq/iii
• https://github.com/iii-hq/iii#readme