Frequently Asked Questions
Use Node.js with Express and the Vonage Messages API to build a backend API. This API can manage contacts, create targeted campaigns, send messages, and handle delivery receipts and opt-out requests. The provided tutorial walks through the entire process of building a production-ready SMS campaign system.
The Vonage Messages API is a unified platform for sending and receiving messages across multiple channels, including SMS. In this tutorial, it's the core component for sending SMS messages within your Node.js application and enables features such as delivery receipts and inbound message handling.
PostgreSQL is used as the database to store contact information, campaign details, and individual message logs. Its robust features ensure data integrity and efficient querying for managing large-scale SMS campaigns and tracking message statuses effectively.
ngrok is essential during development for exposing your local server to the internet. This allows Vonage to send webhooks (message status updates and inbound messages) to your local development environment, which is crucial for testing your application's webhook handling logic.
Although not explicitly covered in the base tutorial, the architecture allows for personalization. By integrating contact data into your message sending logic, you can tailor messages to individual recipients or segments. Further enhancements can be made by incorporating templating engines or other customization tools.
The API includes functionality for managing a contact list and handling opt-out requests. Users can opt out by sending keywords like "STOP". The system checks the opt-out status before sending messages, ensuring compliance with regulations and user preferences.
Express simplifies the creation of the Node.js backend API by providing a minimalist web framework. It handles routing, middleware, and request/response management, making the API development process more efficient and structured.
Vonage sends delivery receipts (message status updates) to your application via webhooks. You'll set up a specific route in your Express app to handle these status updates and update the message logs in your PostgreSQL database accordingly.
Install the @vonage/server-sdk package using npm. Initialize the Vonage client in your Node.js application using your Vonage API key, secret, application ID, and private key. Ensure your private key is stored securely, preferably outside the project root.
You'll need Node.js, npm, a Vonage API account with a virtual phone number, access to a PostgreSQL database, ngrok, and basic knowledge of REST APIs and SQL. These components are essential for building and running the SMS campaign API.
The tutorial recommends a structured project layout including folders for controllers, models, routes, services, config, and utils. This organization enhances code maintainability and scalability, making the project easier to manage and extend.
Set up a webhook route in your Express app that Vonage can call when a user sends an SMS to your virtual number. The tutorial demonstrates how to process inbound messages, particularly for handling opt-out keywords like "STOP".
The dotenv package loads environment variables from a .env file. This keeps sensitive data like API keys and database credentials separate from your code, improving security practices and making configuration easier.
The tutorial provides SQL commands for creating the necessary database tables: contacts, campaigns, and messages. It also covers creating indexes and triggers for optimized performance and data integrity.
While deployment is not extensively covered in the tutorial, it provides a solid foundation for a production-ready system. Deployment would involve configuring your chosen environment, setting up environment variables securely, and ensuring your database and Vonage API are accessible.
Build SMS Marketing Campaigns with Vonage, Express, and PostgreSQL: Complete Production Guide
Build a robust SMS marketing campaign system using Sinch Messages API, Next.js, and Supabase PostgreSQL. This comprehensive guide covers everything from initial setup and bulk SMS sending to implementing TCPA-compliant opt-out handling, real-time delivery tracking, and production deployment.
By the end of this tutorial, you will have a functional SMS marketing platform capable of:
This guide provides a solid foundation for a production-ready system, going beyond simple send/receive examples.
Target Audience: Developers familiar with Node.js, Next.js API Routes, REST APIs, SQL databases, and basic web security concepts.
Technologies Used:
@sinch/sdk-core: Official Sinch Node.js SDK@supabase/supabase-js: Supabase JavaScript clientdotenv: Module for loading environment variablesuuid: Generates unique identifiersngrok: Exposes local development server to the internet for webhook testingRequired Package Versions:
System Architecture:
Data Flow:
/api/campaigns/:id/sendendpoint/api/webhooks/status/api/webhooks/inboundPrerequisites:
ngrokinstalled and authenticated (free account sufficient). Get ngrok1. Setting up the Project
Create the project structure_ install dependencies_ and configure the environment.
1.1 Create Next.js Project
Open your terminal and run:
1.2 Install Dependencies
Install the necessary libraries:
@sinch/sdk-core: Sinch SDK for Node.js@supabase/supabase-js: Supabase client libraryuuid: Generates unique IDs (e.g._ for messages)dotenv: Loads environment variables from a.env.localfile1.3 Project Structure
Create the following directory structure within your project root:
1.4 Environment Configuration (
.env.local)Create a file named
.env.localin the project root. This file stores sensitive credentials and configuration settings. Never commit this file to version control.Environment variables follow the 12-factor app methodology_ separating config from code for portability and security.
Generate a secure random API key:
Use the output as your
API_KEYvalue.API_KEY: A simple key for basic API authentication (replace with a secure, generated key).1.5 Git Ignore (
.gitignore)Ensure your
.gitignorefile (created by Next.js) includes:1.6 Configure Webhooks with ngrok
Sinch webhooks require publicly accessible URLs. During development, use
ngrokto expose your local server.Start ngrok:
Copy the ngrok URL (e.g.,
https://abc123.ngrok.io).Update Sinch Dashboard:
https://abc123.ngrok.io/api/webhooks/inboundhttps://abc123.ngrok.io/api/webhooks/statusNote: ngrok URLs change on restart unless you have a paid account with reserved domains. Update the webhooks each time you restart ngrok.
2. Implementing Core Functionality
Set up the Supabase connection, Sinch client, and basic logging utilities.
2.1 Basic Logger (
src/lib/logger.ts)A simple logger for now. For production applications, upgrade to
winstonorpinofor features like log levels, file rotation, structured logging, and transport to log aggregation services (ELK stack, Datadog, CloudWatch).2.2 TypeScript Types (
src/lib/types.ts)Define common types for type safety:
2.3 Supabase Client Initialization (
src/lib/supabase.ts)Set up the Supabase client using credentials from the
.env.localfile:2.4 Sinch Client Initialization (
src/lib/sinch.ts)Initialize the Sinch SDK using credentials from the
.env.localfile:3. Creating a Database Schema and Data Layer
Create tables in Supabase PostgreSQL to store contacts, campaigns, and individual message statuses.
3.1 Database Schema (SQL)
Execute these SQL commands in your Supabase SQL Editor (Dashboard > SQL Editor).
Enable UUID Extension:
Create Tables:
3.2 Data Services (
src/services/)Create service files to handle database interactions.
Contact Service (
src/services/contactService.ts):Campaign Service (
src/services/campaignService.ts):Sinch Service (
src/services/sinchService.ts):4. Building the API Layer (Next.js API Routes)
Define the RESTful API endpoints using Next.js API Routes for managing contacts, campaigns, and handling webhooks.
4.1 Authentication Middleware
Create a utility function for API key authentication:
4.2 Contact Routes (
src/app/api/contacts/route.ts)4.3 Campaign Routes
List/Create Campaigns (
src/app/api/campaigns/route.ts):Send Campaign (
src/app/api/campaigns/[id]/send/route.ts):Get Campaign Messages (
src/app/api/campaigns/[id]/messages/route.ts):4.4 Webhook Routes
Inbound Messages (
src/app/api/webhooks/inbound/route.ts):Status Updates (
src/app/api/webhooks/status/route.ts):5. Testing Your API
Test your endpoints using curl or Postman.
5.1 Start the Development Server
5.2 Test Endpoints with curl
Create a Contact:
Expected Response (201 Created):
Get All Contacts:
Create a Campaign:
Send Campaign:
Expected Response (202 Accepted):
Get Campaign Messages:
6. Deployment Considerations
Deploy your SMS campaign API to production using Vercel, the recommended platform for Next.js applications.
6.1 Deploy to Vercel
Using Vercel CLI:
Using GitHub Integration:
6.2 Environment Variables for Production
Set these in Vercel Dashboard (Settings > Environment Variables):
SINCH_PROJECT_IDSINCH_KEY_IDSINCH_KEY_SECRETSINCH_NUMBERNEXT_PUBLIC_SUPABASE_URLNEXT_PUBLIC_SUPABASE_ANON_KEYSUPABASE_SERVICE_ROLE_KEYAPI_KEY6.3 Update Sinch Webhooks
After deployment, update your Sinch webhook URLs to point to your production domain:
https://your-domain.vercel.app/api/webhooks/inboundhttps://your-domain.vercel.app/api/webhooks/status6.4 Alternative Deployment Options
Docker Deployment:
Build and run:
7. Monitoring and Observability
Implement monitoring to track API health, performance, and errors.
7.1 Vercel Analytics
Enable Vercel Analytics in your project:
Add to
src/app/layout.tsx:7.2 Supabase Logging
Query logs in Supabase Dashboard:
7.3 Application Performance Monitoring (APM)
Option 1: Sentry
Option 2: Datadog
Frequently Asked Questions (FAQ)
How do I build an SMS marketing campaign system with Sinch and Next.js?
Build an SMS marketing system by creating a Next.js application with API routes that manage contacts in Supabase PostgreSQL, use the Sinch Messages API to send bulk SMS via
@sinch/sdk-core, implement webhooks for delivery receipts and opt-out handling, and include campaign tracking tables to monitor message status and engagement metrics.What database schema do I need for SMS campaign management with Supabase?
An SMS campaign database requires three core tables:
contacts(storing phone numbers in E.164 format with opt-out status),campaigns(tracking campaign name, message text, status, and scheduling), andmessages(logging individual SMS delivery with Sinch message IDs, status updates, timestamps, and error codes). Add indexes on phone_number, sinch_message_id, and foreign keys for optimal query performance.How do I handle STOP and opt-out requests in SMS marketing?
Handle opt-out requests by creating a webhook endpoint that receives inbound SMS messages, checks for keywords like "STOP", "UNSUBSCRIBE", "CANCEL", "END", or "QUIT", updates the contact's
opted_outstatus in your Supabase database, and excludes opted-out contacts from future campaign sends. This ensures compliance with TCPA regulations and carrier requirements.What is the Sinch Messages API authentication method?
Sinch Messages API uses project-based authentication requiring a Project ID, Key ID, and Key Secret. Generate these in the Sinch Dashboard under Settings > API Credentials, and initialize the SDK with
new SinchClient({ projectId, keyId, keySecret }). Store credentials securely using environment variables. Never commit API keys to version control.How do I send bulk SMS campaigns without hitting rate limits?
Send bulk campaigns by implementing asynchronous processing with controlled concurrency, adding delays between sends (e.g., 100–200ms), using campaign status tracking to resume failed sends, implementing exponential backoff for API errors, and monitoring Sinch's rate limits (typically 30–60 SMS per second depending on account tier). Consider using a job queue like BullMQ for large campaigns.
How do I track SMS delivery status with Sinch webhooks?
Track delivery status by configuring a status webhook URL in your Sinch Dashboard settings, creating a POST endpoint (e.g.,
/api/webhooks/status) that receives Sinch delivery receipts, parsing thebatch_idandstatusfields (delivered, expired, failed, rejected), and updating your messages table. Storestatus_timestamp,error_code, anderror_messagefor failed deliveries to analyze campaign performance.What are E.164 phone number format requirements for SMS?
E.164 is the international telephone numbering standard (ITU-T Recommendation E.164) requiring phone numbers in format: + [country code] [subscriber number including area code], with maximum 15 digits excluding the + symbol. Store numbers as VARCHAR(20) in PostgreSQL, validate format using libphonenumber-js library before database insertion, and reject invalid numbers to prevent API errors and wasted credits.
How do I secure my SMS marketing API endpoints in Next.js?
Secure SMS marketing APIs by implementing API key authentication middleware for campaign and contact routes (using
x-api-keyheader), excluding webhooks from API key auth since Sinch calls them, validating all input with Zod or similar validation libraries, using Supabase RLS (Row Level Security) policies for data access control, and implementing webhook signature verification or IP allowlisting for production environments.How do I integrate Supabase with Next.js for SMS campaigns?
Integrate Supabase with Next.js by installing
@supabase/supabase-js, creating a client instance with your Project URL and service role key for server-side operations, using the service role key in API routes for bypassing RLS, implementing TypeScript types matching your database schema, and leveraging Supabase's real-time features for live campaign monitoring and status updates.What is the best way to handle SMS campaign analytics in Supabase?
Handle SMS campaign analytics by creating PostgreSQL views that aggregate message statuses by campaign, implementing SQL queries for delivery rates and engagement metrics, using Supabase functions to calculate KPIs like open rates and opt-out rates, creating materialized views for performance optimization, and exposing analytics through Next.js API routes with proper caching and pagination.
Related Resources
Sinch SMS Integration Guides:
Next.js SMS Campaign Guides:
Supabase & Database Best Practices:
SMS Compliance & Best Practices: