Just like you can execute multiple JavaScript promises at the same time using Promise.all, you can run multiple workflow steps at the same time:

const [result1, result2, result3] =
  await Promise.all([
    ctx.run("parallel-step-1", async () => { ... }),
    ctx.run("parallel-step-2", async () => { ... }),
    ctx.run("parallel-step-3", async () => { ... }),
  ])

In a complete code example, your workflow could look like this:

app/api/workflow/route.ts
import { serve } from "@upstash/workflow/nextjs"
import { checkInventory, brewCoffee, printReceipt } from "@/utils"

export const { POST } = serve(async (ctx) => {
  const [coffeeBeansAvailable, cupsAvailable, milkAvailable] =
    await Promise.all([
      ctx.run("check-coffee-beans", () => checkInventory("coffee-beans")),
      ctx.run("check-cups", () => checkInventory("cups")),
      ctx.run("check-milk", () => checkInventory("milk")),
    ])

  // If all ingedients available, brew coffee
  if (coffeeBeansAvailable && cupsAvailable && milkAvailable) {
    const price = await ctx.run("brew-coffee", async () => {
      return await brewCoffee({ style: "cappuccino" })
    })

    await printReceipt(price)
  }
})

After running your workflow, your dashboard shows each step in detail: