Parallel Execution with Steps ✅

When building AI applications, you often need to process multiple independent tasks simultaneously to improve efficiency.

Control Flow Diagram ✅

This example shows how to structure a workflow that executes steps in parallel, with each branch handling its own data flow and dependencies.

Here’s the control flow diagram:

Diagram showing workflow with parallel steps

Creating the Steps ✅

Let’s start by creating the steps and initializing the workflow.


import { Step, Workflow } from "@kastrax/core/workflows";
import { z } from "zod";
 
const stepOne = new Step({
  id: "stepOne",
  execute: async ({ context }) => ({
    doubledValue: context.triggerData.inputValue * 2,
  }),
});
 
const stepTwo = new Step({
  id: "stepTwo",
  execute: async ({ context }) => {
    if (context.steps.stepOne.status !== "success") {
      return { incrementedValue: 0 }
    }
 
    return { incrementedValue: context.steps.stepOne.output.doubledValue + 1 }
  },
});
 
const stepThree = new Step({
  id: "stepThree",
  execute: async ({ context }) => ({
    tripledValue: context.triggerData.inputValue * 3,
  }),
});
 
const stepFour = new Step({
  id: "stepFour",
  execute: async ({ context }) => {
    if (context.steps.stepThree.status !== "success") {
      return { isEven: false }
    }
 
    return { isEven: context.steps.stepThree.output.tripledValue % 2 === 0 }
  },
});
 
const myWorkflow = new Workflow({
  name: "my-workflow",
  triggerSchema: z.object({
    inputValue: z.number(),
  }),
});

Chaining and Parallelizing Steps ✅

Now we can add the steps to the workflow. Note the .then() method is used to chain the steps, but the .step() method is used to add the steps to the workflow.


myWorkflow
  .step(stepOne)
    .then(stepTwo) // chain one
  .step(stepThree)
    .then(stepFour) // chain two
  .commit();
 
const { start } = myWorkflow.createRun();
 
const result = await start({ triggerData: { inputValue: 3 } });

View Example on GitHub