TanStack Start

Set up your first durable workflow in a TanStack Start application.

This guide will walk through setting up your first workflow in a TanStack Start app. Along the way, you'll learn more about the concepts that are fundamental to using the Workflow SDK in your own projects.

Start by creating a new TanStack Start project:

npx @tanstack/cli create my-workflow-app

Enter the newly made directory:

Install `workflow`

Configure TanStack Start

TanStack Start runs on Vite, so the Workflow SDK is wired in via the same workflow/vite plugin. Add workflow() to the existing plugins array in your Vite config — list it first so the "use workflow" and "use step" transforms run before any other plugin processes the file.

import { defineConfig } from "vite";
import { workflow } from "workflow/vite";
// ...

export default defineConfig({
  plugins: [
    workflow(), 
    // ...the existing tanstackStart(), nitro(), and any other plugins
  ],
});

Create a new file for our first workflow:

import { sleep } from "workflow";

export async function handleUserSignup(email: string) {
  "use workflow"; 

  const user = await createUser(email);
  await sendWelcomeEmail(user);

  await sleep("5s"); // Pause for 5s - doesn't consume any resources
  await sendOnboardingEmail(user);

  return { userId: user.id, status: "onboarded" };
}

We'll fill in those functions next, but let's take a look at this code:

We define a workflow function with the directive "use workflow". Think of the workflow function as the orchestrator of individual steps.
The Workflow SDK's sleep function allows us to suspend execution of the workflow without using up any resources. A sleep can be a few seconds, hours, days, or even months long.

Let's now define those missing functions.

import { FatalError } from "workflow"

// Our workflow function defined earlier

async function createUser(email: string) {
  "use step"; 

  console.log(`Creating user with email: ${email}`);

  // Full Node.js access - database calls, APIs, etc.
  return { id: crypto.randomUUID(), email };
}

async function sendWelcomeEmail(user: { id: string; email: string; }) {
  "use step"; 

  console.log(`Sending welcome email to user: ${user.id}`);

  if (Math.random() < 0.3) {
  // By default, steps will be retried for unhandled errors
   throw new Error("Retryable!");
  }
}

async function sendOnboardingEmail(user: { id: string; email: string}) {
  "use step"; 

  if (!user.email.includes("@")) {
    // To skip retrying, throw a FatalError instead
    throw new FatalError("Invalid Email");
  }

  console.log(`Sending onboarding email to user: ${user.id}`);
}

Taking a look at this code:

Business logic lives inside steps. When a step is invoked inside a workflow, it gets enqueued to run on a separate request while the workflow is suspended, just like sleep.
If a step throws an error, like in sendWelcomeEmail, the step will automatically be retried until it succeeds (or hits the step's max retry count).
Steps can throw a FatalError if an error is intentional and should not be retried.

We'll dive deeper into workflows, steps, and other ways to suspend or handle events in Foundations.

To invoke your new workflow, add a server handler at src/routes/api/signup.ts:

import { createFileRoute } from "@tanstack/react-router";
import { json } from "@tanstack/react-start";
import { start } from "workflow/api";
import { handleUserSignup } from "../../workflows/user-signup";

export const Route = createFileRoute("/api/signup")({
  server: {
    handlers: {
      POST: async ({ request }) => {
        const { email } = await request.json();
        // Executes asynchronously and doesn't block your app
        await start(handleUserSignup, [email]);
        return json({ message: "User signup workflow started" });
      },
    },
  },
});

This route handler creates a POST request endpoint at /api/signup that will trigger your workflow.

Workflows can be triggered from API routes or any server-side code.

To start your development server, run the following command in your terminal in the TanStack Start root directory:

Once your development server is running, you can trigger your workflow by running this command in the terminal:

curl -X POST --json '{"email":"hello@example.com"}' http://localhost:3000/api/signup

Check the dev server logs to see your workflow execute as well as the steps that are being processed.

Additionally, you can use the Workflow SDK CLI or Web UI to inspect your workflow runs and steps in detail.

# Open the observability Web UI on http://localhost:3456
npx workflow web
# or if you prefer a terminal interface, use the CLI inspect command
npx workflow inspect runs

Workflow SDK Web UI

Workflow SDK apps currently work best when deployed to Vercel and needs no special configuration.

Enable Fluid compute before deploying. Workflow is designed to take advantage of Fluid compute for efficient suspension and resumption. Without Fluid compute enabled, each workflow resume incurs a separate function cold start, which can result in significantly higher costs.

Check the Deploying section to learn how your workflows can be deployed elsewhere.

Learn more about the Foundations.
Check Errors if you encounter issues.
Explore the API Reference.

推荐订阅源

Workflow SDK Documentation

Install `workflow`

Configure TanStack Start

推荐订阅源

Workflow SDK Documentation

Install workflow

Configure TanStack Start

Install `workflow`