You'll need Node.js, npm/yarn, NestJS CLI, Docker, Docker Compose, a Vonage API account with a Vonage phone number, and ngrok for local webhook testing.

Use the Vonage Messages API integrated with a NestJS service. The Vonage Node.js SDK simplifies sending SMS messages by providing methods to manage API requests and responses. Make sure to configure the Vonage service with your API credentials from the Vonage dashboard and inject this service into your NestJS campaign service or controller where you'll handle sending logic.

The Vonage Messages API is a service that allows you to send and receive SMS messages programmatically. It's a key component for building SMS marketing campaigns, and you interact with it using the Vonage Node.js SDK within your NestJS application. It also handles message status updates and inbound messages via webhooks.

TypeORM is used for database interaction with PostgreSQL. It provides an object-relational mapper (ORM) simplifying database operations in NestJS. TypeORM defines entities (Campaign, Subscriber, MessageLog) to represent database tables, allowing interaction using JavaScript/TypeScript objects and methods.

Ngrok is useful for testing webhooks locally during development when your local server isn't publicly accessible. It creates a temporary public URL that forwards requests to your local machine. For production, you'll need a stable public URL on a server or platform-as-a-service (PaaS).

Yes, TypeORM supports various databases like MySQL, MongoDB, and more. While the guide uses PostgreSQL, you can adapt the TypeORM configuration in your AppModule to connect to your preferred database. Remember to install the appropriate database driver and adjust connection details accordingly.

Access your Vonage API Dashboard, ensure 'Messages API' is selected under Default SMS settings. Create a new Vonage Application, enabling the 'Messages' capability. Save the private key file securely and note the Application ID. Link your Vonage number to this application so incoming messages are routed to your app's webhook.

The guide recommends a modular structure with separate modules for campaigns, subscribers, Vonage API integration, webhooks, and database operations. This keeps the code organized, maintainable, and easy to test. Create modules using the NestJS CLI and organize related code within each module.

Use the @nestjs/config module to load environment variables from a .env file. Store API keys, database credentials, and other sensitive information in .env and ensure it's added to your .gitignore file. Never commit .env to version control.

The Vonage service provides a verifyWebhookJwt method. You should implement this method by retrieving the Vonage public key or signature secret from your config and using it to verify the webhook signature using the Vonage SDK method or appropriate JWT libraries. This ensures the webhook request is indeed from Vonage.

The guide suggests creating a subscribers module with a service and controller to manage subscriber data. You'll need to implement endpoints and methods to store and retrieve subscribers from the database using TypeORM. Ensure you collect necessary subscriber data like phone numbers.

Consider techniques such as asynchronous message sending with queues or message batching instead of the simple sequential sending in the example. Rate limiting should be carefully managed, potentially with external tools or libraries, if higher throughput is needed.

The private.key file contains your Vonage application's private key, used to authenticate with the Vonage API. It is crucial for security, and should never be committed to version control. Store it securely in your project directory and add it to your .gitignore file.

DTOs provide a structured way to define and validate data coming from external sources like API requests. By using class-validator decorators in DTOs, you can easily apply validation rules ensuring data integrity and security.