Iii

iii is an engine for connecting functions, agents, APIs, models, browsers and machines into a single live system. The vendor describes it as the layer underneath agent frameworks and workflow engines, offering the convenience of a platform without lock in. Its design rests on three primitives: Function, Trigger and Worker. A trigger starts work, the engine runs each function call, and one trace follows a request from start to finish. Developers write functions in TypeScript, Python or Rust, and these can run across languages, processes and machines while still calling one another. Workers are defined in a Compose file and started with a single command on infrastructure the user controls, bringing up services such as HTTP, database, storage, queue, cron and state. The same functions can back an application platform or a custom agent harness, where teams choose model providers such as Anthropic and OpenAI, tools and session behavior. The site publishes benchmark figures measured on a GitHub hosted runner, including call overhead in the low microseconds. It is aimed at engineering teams building backends and agent systems who want one runtime rather than separate services for each concern. Installation is through a command line installer, and release notes arrive by email. The vendor does not publish any pricing, so cost and licensing terms are not stated on the home page.