Temporal Workflow Demo 🚀

This repository demonstrates how Temporal can be used for distributed workflow orchestration in a modern TypeScript monorepo. It showcases how Temporal handles complex business processes across multiple services with built-in reliability.

Built With

• Temporal - Workflow orchestration ⚡
• TypeScript - Language 💪
• Express - API framework 🌐
• Turborepo - Monorepo tooling 🛠️

Overview 📋

The demo implements an investment workflow that spans multiple services:

graph LR
    API[REST API] --> T[Temporal Server]
    T --> IW[Investment Worker]
    IW --> T
    T --> EW[Email Worker]

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• apps/api: REST API that initiates workflows
• apps/investment-worker: Handles investment processing
• apps/email-worker: Manages email notifications
• Temporal Server: Orchestrates the entire workflow

Getting Started 🏃

1. Install dependencies:

pnpm install

2. Start Temporal Server:

pnpm temporal  # or pnpm temporal:start

# To stop the server later:
pnpm temporal:stop

3. Start all services:

pnpm dev

This will start:

• API server at http://localhost:3000
• Investment worker
• Email worker
• Temporal UI at http://localhost:8080

Try It Out ✨

Make an investment request:

# Start an investment workflow
curl -X POST http://localhost:3000/invest \
  -H "Content-Type: application/json" \
  -d '{
    "userId": "user123",
    "amount": 1000
  }'

# Response:
# {
#   "workflowId": "investment-user123-1234567890"
# }

The workflow will:

1. Record the investment (handled by investment-worker)
2. Send a confirmation email (handled by email-worker)
3. You can watch the progress in the logs or Temporal UI

Example: Workflow Resilience 💪

Here's a demonstration of Temporal's durability:

1. Start a workflow as shown above
2. Investment worker logs:

Investment workflow started { userId: 'user123', amount: 1000 }
Investment recorded { userId: 'user123' }
[Process exits unexpectedly]

3. The workflow will pause. Start the services again:

pnpm dev

4. Watch it continue automatically:

Worker connected, waiting for tasks...
Starting email workflow { userId: 'user123' }
Investment workflow completed { userId: 'user123' }

The workflow continues without any data loss or manual intervention! 🎉

Project Structure 📁

apps/
  ├── api/              # REST API
  ├── investment-worker # Investment processing service
  └── email-worker     # Email notification service
infra/
  └── temporal/        # Temporal server configuration

Sample Output 📝

When you run the workflow, you'll see the following logs:

Investment Worker

Worker connected, waiting for tasks...
2025-08-17T12:20:13.521Z [INFO] Worker state changed {
  sdkComponent: 'worker',
  taskQueue: 'investment-queue',
  state: 'RUNNING'
}
2025-08-17T12:20:31.037Z [INFO] Investment workflow started {
  sdkComponent: 'workflow',
  taskQueue: 'investment-queue',
  namespace: 'default',
  workflowId: 'investment-user2-1755433230984',
  runId: '0198b7f9-628b-7a13-999c-4bbd8e1b8366',
  workflowType: 'investmentWorkflow',
  userId: 'user2',
  amount: 500
}
Recording investment { userId: 'user2', amount: 500 }
Investment saved to memory { userId: 'user2' }
2025-08-17T12:20:31.069Z [INFO] Investment recorded {
  sdkComponent: 'workflow',
  taskQueue: 'investment-queue',
  namespace: 'default',
  workflowId: 'investment-user2-1755433230984',
  runId: '0198b7f9-628b-7a13-999c-4bbd8e1b8366',
  workflowType: 'investmentWorkflow',
  userId: 'user2',
  amount: 500
}
2025-08-17T12:20:31.081Z [INFO] Starting email workflow {
  sdkComponent: 'workflow',
  taskQueue: 'investment-queue',
  namespace: 'default',
  workflowId: 'investment-user2-1755433230984',
  runId: '0198b7f9-628b-7a13-999c-4bbd8e1b8366',
  workflowType: 'investmentWorkflow',
  userId: 'user2'
}
2025-08-17T12:20:31.096Z [INFO] Investment workflow completed {
  sdkComponent: 'workflow',
  taskQueue: 'investment-queue',
  namespace: 'default',
  workflowId: 'investment-user2-1755433230984',
  runId: '0198b7f9-628b-7a13-999c-4bbd8e1b8366',
  workflowType: 'investmentWorkflow',
  userId: 'user2'
}

Email Worker

2025-08-17T12:20:13.521Z [INFO] Worker state changed { sdkComponent: 'worker', taskQueue: 'email-queue', state: 'RUNNING' }
2025-08-17T12:20:31.133Z [INFO] Email workflow started {
  sdkComponent: 'workflow',
  taskQueue: 'email-queue',
  namespace: 'default',
  workflowId: 'email-user2-1755433231075',
  runId: '0198b7f9-62ed-7d55-8f07-0e34e14dc45a',
  workflowType: 'sendEmailWorkflow',
  to: 'user2@example.com'
}

=== Simulated Email ===
To: user2@example.com
Subject: Investment Confirmation
Body: Your investment of $500 has been received.
====================

Email sent successfully
2025-08-17T12:20:31.680Z [INFO] Email workflow completed {
  sdkComponent: 'workflow',
  taskQueue: 'email-queue',
  namespace: 'default',
  workflowId: 'email-user2-1755433231075',
  runId: '0198b7f9-62ed-7d55-8f07-0e34e14dc45a',
  workflowType: 'sendEmailWorkflow',
  to: 'user2@example.com'
}

These logs show the complete flow:

1. Investment worker receives and processes the investment
2. Triggers the email workflow
3. Email worker receives and processes the email request
4. Both workflows complete successfully