Experts.js is a JavaScript framework that makes it easy to create and deploy OpenAI Assistants and link them together as tools, forming multi-agent systems with expanded memory and attention to detail. Built by MetaSkills, the tech team behind Custom Ink, and released under the MIT license, it has earned over 1,000 stars on GitHub.
The library builds on OpenAI’s Assistants API: you define expert assistants in code, then connect them into a panel of experts where one assistant can call another as a tool to handle specialized sub-tasks. That composition pattern lets you build systems that reason across domains — a researcher expert feeding a writer expert, for example — while each assistant keeps its own instructions, model settings, and file knowledge. Experts.js handles the API plumbing, including threads and runs, so developers can focus on agent design rather than request choreography. The project site collects examples and documentation to get a first panel of experts running quickly, and the framework pairs naturally with models such as GPT-4o mini for cost-effective deployments.
In practice, the framework shines when a single assistant would need an unwieldy system prompt: splitting responsibilities across experts keeps each assistant’s instructions short and testable, and lets you swap or upgrade one expert without redesigning the whole system. Because experts communicate through the same tool-calling mechanism the Assistants API already provides, the architecture stays native to OpenAI’s platform — threads, files, and function calling behave as documented — while Experts.js supplies the composition layer that the raw API leaves to you.
Experts.js is free and open source under the MIT license. Usage costs come only from your own OpenAI API consumption.
It is aimed at JavaScript and TypeScript developers who want structured multi-agent behavior on top of OpenAI’s platform without hand-rolling the Assistants API.