Unify backend services and observation into a single real-time system
iii bundles backend components that previously required different integration methods—such as queues, cron jobs, HTTP, state management, agents, and sandboxes—into one real-time system. It simplifies these elements into three core concepts: workers, triggers, and functions. This allows developers to focus on business logic without needing separate configuration or integration steps for new features, which are reflected in the running system immediately.
Building a real-time system with three core elements
iii defines all services using three concepts: workers, triggers, and functions. A worker is a process registered with the iii engine that provides triggers and functions; whether it is a TypeScript API service or a Python data pipeline, it can be converted into a worker with a few lines of code. A trigger is anything that causes a function to execute, including direct calls, HTTP endpoints, cron schedules, queue subscriptions, and state changes. A function is a unit of work with a stable identifier, such as content::classify, that takes input, performs the task, and optionally returns output. This structure allows the system to add new workers while running, which other workers can immediately discover and call.
An interface shared by agents and developers
iii is designed so that developers and AI agents use the same interface. When an agent needs a feature not present in the system, it can add a worker, discover that worker's functions, call them, and track the resulting events. This is the same process used by developers. Platform teams publish workers, application teams register functions and declare triggers, and agents use the same catalog and function calls. Because extension, configuration, and observation all use the same mechanism, system complexity is significantly reduced.
Installation and adding workers
iii can be installed using the command curl -fsSL https://install.iii.dev/iii/main/install.sh | sh. Workers can be declared in a worker-compose.yaml file or added via a running Compose daemon using commands like iii trigger -n dev compose::add worker=queue. SDKs are provided for Node.js, Python, Rust, and Go, allowing easy integration in each language environment. iii-console is a developer and operations console for inspecting workers, functions, triggers, queues, traces, logs, and real-time status, used to understand the system's state in real time.
License structure and considerations
The iii repository uses different licenses for different directories. The engine runtime (engine/) is under the Elastic License 2.0 (ELv2), while the SDK, CLI, console, documentation, and website are under the Apache License 2.0. Since ELv2 has specific restrictions, you must review the license terms if you modify or redistribute the engine directly. Additionally, because iii aims to integrate all services into a real-time system surface, it is recommended to review compatibility with existing systems and data consistency requirements in advance. Agent skills can be installed with npx skills add iii-hq/iii/skills, and individual worker skills can also be installed.