LlamaIndex Workflows

LlamaIndex Workflows are a library for event-driven programming in JavaScript and TypeScript. It provides a simple and lightweight orchestration solution for building complex workflows with minimal boilerplate.

It combines event-driven programming, async context and streaming to create a flexible and efficient way to handle data processing tasks.

The essential concepts of Workflows are:

Events: are the core building blocks of Workflows. They represent data that flows through the system.
Handlers: are functions that process events and can produce new events.
Context: is the environment in which events are processed. It provides access to the event stream and allows sending new events.
Workflow: is the collection of events, handlers, and context that define the processing logic.

Getting Started

npm i @llamaindex/workflow-core

yarn add @llamaindex/workflow-core

pnpm add @llamaindex/workflow-core

bun add @llamaindex/workflow-core

deno add npm:@llamaindex/workflow-core

First Example

With workflowEvent and createWorkflow, you can create a simple workflow that processes events.

For example, imagine you want to create a workflow that uses OpenAI to generate a response to a user’s message.

import { OpenAI } from "openai";
import { createWorkflow, workflowEvent } from "@llamaindex/workflow-core";

const main = async () => {
  const openai = new OpenAI({
    apiKey: process.env.OPENAI_API_KEY,
  });

  const startEvent = workflowEvent<string>();
  const stopEvent = workflowEvent<string>();

  const workflow = createWorkflow();

  workflow.handle([startEvent], async (event) => {
    const response = await openai.chat.completions.create({
      model: "gpt-4.1-mini",
      messages: [{ role: "user", content: event.data }],
    });

    return stopEvent.with(response.choices[0].message.content ?? "");
  });

  workflow.handle([stopEvent], (event) => {
    console.log("Response:", event.data);
  });

  const { sendEvent } = workflow.createContext();
  sendEvent(startEvent.with("Hello, Workflows!"));
};

void main().catch(console.error);

From here, the sky is the limit. You can implement branching, looping, human-in-the-loop, map-reduce, and more!

Architecture

Workflows are built around components like events, steps/handlers, context, and more. Learn more about these components here.

Deployment

Workflows are designed to be run anywhere. Deploy in a server, a lambda function, an edge runtime, or a cloudflare function!

LlamaIndex Workflows

Getting Started

First Example

Architecture

Deployment

Community