workflow
Version:
Workflow DevKit - Build durable, resilient, and observable workflows
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text/mdx
---
title: NestJS
description: Set up your first durable workflow in a NestJS application.
type: guide
summary: Set up Workflow DevKit in a NestJS app.
prerequisites:
- /docs/getting-started
related:
- /docs/foundations/workflows-and-steps
---
This guide will walk through setting up your first workflow in a NestJS app. Along the way, you'll learn more about the concepts that are fundamental to using the development kit in your own projects.
---
<Steps>
<Step>
## Create Your NestJS Project
Start by creating a new NestJS project using the NestJS CLI.
```bash
npm i -g /cli
nest new my-workflow-app
```
Enter the newly made directory:
```bash
cd my-workflow-app
```
### Install `workflow`
```package-install
npm i workflow /nest
```
### Configure NestJS for ESM
NestJS with SWC uses ES modules. Add `"type": "module"` to your `package.json`:
```json title="package.json" lineNumbers
{
"name": "my-workflow-app",
"type": "module",
// ... rest of your config
}
```
<Callout>
When using ESM with NestJS, local imports must include the `.js` extension (e.g., `import { AppModule } from './app.module.js'`). This applies even though your source files are `.ts`.
</Callout>
### Configure NestJS to use SWC
NestJS supports SWC as an alternative compiler for faster builds. The Workflow DevKit uses an SWC plugin to transform workflow files.
Install the required SWC packages:
```package-install
npm i -D /cli @swc/core
```
Ensure your `nest-cli.json` has SWC as the builder:
```json title="nest-cli.json" lineNumbers
{
"$schema": "https://json.schemastore.org/nest-cli",
"collection": "@nestjs/schematics",
"sourceRoot": "src",
"compilerOptions": {
"builder": "swc",
"deleteOutDir": true
}
}
```
### Initialize SWC Configuration
Run the init command to generate the SWC configuration:
```bash
npx /nest init
```
This creates a `.swcrc` file configured with the Workflow SWC plugin for client-mode transformations.
<Callout>
Add `.swcrc` to your `.gitignore` as it contains machine-specific absolute paths that shouldn't be committed.
</Callout>
### Update `package.json`
Add scripts to regenerate the SWC configuration before builds:
```json title="package.json" lineNumbers
{
"scripts": {
"prebuild": "npx @workflow/nest init --force",
"build": "nest build",
"start:dev": "npx @workflow/nest init --force && nest start --watch"
}
}
```
<Accordion type="single" collapsible>
<AccordionItem value="typescript-intellisense" className="[&_h3]:my-0">
<AccordionTrigger className="[&_p]:my-0 text-lg [&_p]:text-foreground">
Setup IntelliSense for TypeScript (Optional)
</AccordionTrigger>
<AccordionContent className="[&_p]:my-2">
To enable helpful hints in your IDE, setup the workflow plugin in `tsconfig.json`:
```json title="tsconfig.json" lineNumbers
{
"compilerOptions": {
// ... rest of your TypeScript config
"plugins": [
{
"name": "workflow" // [!code highlight]
}
]
}
}
```
</AccordionContent>
</AccordionItem>
</Accordion>
</Step>
<Step>
## Import the WorkflowModule
In your `app.module.ts`, import the `WorkflowModule`:
```typescript title="src/app.module.ts" lineNumbers
import { Module } from '@nestjs/common';
import { WorkflowModule } from '@workflow/nest';
import { AppController } from './app.controller.js';
import { AppService } from './app.service.js';
({
imports: [WorkflowModule.forRoot()], // [!code highlight]
controllers: [AppController],
providers: [AppService],
})
export class AppModule {}
```
The `WorkflowModule` handles workflow bundle building and provides HTTP routing for workflow execution at `.well-known/workflow/v1/`.
</Step>
<Step>
## Create Your First Workflow
Create a new file for our first workflow in the `src/workflows` directory:
<Callout>
Workflow files must be inside the `src/` directory so they get compiled with the SWC plugin that enables the `start()` function to work correctly.
</Callout>
```typescript title="src/workflows/user-signup.ts" lineNumbers
import { sleep } from "workflow";
export async function handleUserSignup(email: string) {
"use workflow"; // [!code highlight]
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 DevKit'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.
## Create Your Workflow Steps
Let's now define those missing functions.
```typescript title="src/workflows/user-signup.ts" lineNumbers
import { FatalError } from "workflow";
// Our workflow function defined earlier
async function createUser(email: string) {
"use step"; // [!code highlight]
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"; // [!code highlight]
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"; // [!code highlight]
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.
<Callout>
We'll dive deeper into workflows, steps, and other ways to suspend or handle
events in [Foundations](/docs/foundations).
</Callout>
</Step>
<Step>
## Create Your Controller
To invoke your new workflow, update your controller with a new endpoint:
{/*@skip-typecheck - NestJS decorators require special TypeScript config*/}
```typescript title="src/app.controller.ts" lineNumbers
import { Body, Controller, Post } from '@nestjs/common';
import { start } from 'workflow/api';
import { handleUserSignup } from './workflows/user-signup.js';
()
export class AppController {
('signup')
async signup(() body: { email: string }) {
await start(handleUserSignup, [body.email]);
return { message: 'User signup workflow started' };
}
}
```
This creates a `POST` endpoint at `/signup` that will trigger your workflow.
</Step>
<Step>
## Run in development
To start your development server, run the following command in your terminal:
```bash
npm run start:dev
```
Once your development server is running, you can trigger your workflow by running this command in the terminal:
```bash
curl -X POST -H "Content-Type: application/json" -d '{"email":"hello@example.com"}' http://localhost:3000/signup
```
Check the NestJS development server logs to see your workflow execute as well as the steps that are being processed.
Additionally, you can use the [Workflow DevKit CLI or Web UI](/docs/observability) to inspect your workflow runs and steps in detail.
```bash
# Open the observability Web UI
npx workflow web
# or if you prefer a terminal interface, use the CLI inspect command
npx workflow inspect runs
```
</Step>
</Steps>
---
## Configuration Options
The `WorkflowModule.forRoot()` method accepts optional configuration:
{/*@skip-typecheck - Configuration snippet, WorkflowModule not imported*/}
```typescript
WorkflowModule.forRoot({
// Directory to scan for workflow files (default: ['src'])
dirs: ['src'],
// Output directory for generated bundles (default: '.nestjs/workflow')
outDir: '.nestjs/workflow',
// Skip building in production when bundles are pre-built
skipBuild: false,
});
```
## Deploying to production
Workflow DevKit apps currently work best when deployed to [Vercel](https://vercel.com/home) and needs no special configuration.
<FluidComputeCallout />
Check the [Deploying](/docs/deploying) section to learn how your workflows can be deployed elsewhere.
## Next Steps
- Learn more about the [Foundations](/docs/foundations).
- Check [Errors](/docs/errors) if you encounter issues.
- Explore the [API Reference](/docs/api-reference).