A multi-day email drip campaign workflow built with Vercel Workflow DevKit. This example demonstrates how to use sleep() to schedule emails over the course of a week without consuming compute resources during wait periods.

• Durable sleep: Using sleep() with duration strings like "1d", "2d", "4d" to pause workflow execution for days without consuming resources
• Multi-step workflows: Breaking down the campaign into discrete steps with "use step" directive
• Workflow orchestration: Using "use workflow" directive to define the main workflow function
• API integration: Starting workflows from a Next.js API route using start()

01-onboarding-drip/
├── app/
│   ├── api/
│   │   └── onboarding/
│   │       └── route.ts      # API endpoint to start the workflow
│   ├── globals.css
│   ├── layout.tsx
│   └── page.tsx
├── workflows/
│   └── onboarding-drip.ts    # The drip campaign workflow
├── next.config.ts            # Uses withWorkflow() wrapper
├── package.json
└── tsconfig.json

1. Install dependencies:

pnpm install

1. Run the development server:

pnpm dev

1. Start an onboarding drip campaign:

curl -X POST http://localhost:3000/api/onboarding \
  -H "Content-Type: application/json" \
  -d '{"email": "user@example.com"}'

Start a new onboarding drip campaign for a user.

Request Body:

{
  "email": "user@example.com"
}

Response:

{
  "message": "Onboarding drip campaign started",
  "runId": "run_abc123",
  "email": "user@example.com",
  "schedule": {
    "day0": "Welcome email (immediate)",
    "day1": "Getting started tips",
    "day3": "Feature highlights",
    "day7": "Follow-up and feedback request"
  }
}

The sleep() function accepts duration strings in the format:

• "7d" - 7 days
• "24h" - 24 hours
• "30m" - 30 minutes
• "10s" - 10 seconds
• "250ms" - 250 milliseconds

Functions that orchestrate steps must include the "use workflow" directive:

export async function runOnboardingDrip(email: string) {
  "use workflow";
  // ...
}

Individual operations that should be tracked and can be retried must include the "use step" directive:

async function sendWelcomeEmail(email: string) {
  "use step";
  // ...
}

To send real emails, integrate with your email provider (Resend, SendGrid, Postmark, etc.) in each step function:

import { Resend } from 'resend';

const resend = new Resend(process.env.RESEND_API_KEY);

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

  await resend.emails.send({
    from: 'onboarding@yourapp.com',
    to: email,
    subject: 'Welcome to Our App!',
    html: '<h1>Welcome!</h1><p>We are excited to have you...</p>'
  });
}