Sending SMS with Node.js, Express, and Sinch - code-examples -

Frequently Asked Questions

Set up an Express server, install Axios and dotenv, create a POST route '/send-sms', and use Axios to send data to the Sinch SMS API. This route will handle incoming requests with the recipient's number and message body, then securely pass this information to the Sinch API to trigger the SMS delivery. Refer to the article's step-by-step guide for detailed instructions and code snippets.
The Sinch SMS REST API is a web service that allows you to send and receive SMS messages programmatically. You interact with it by sending HTTP requests (typically POST) to specific endpoints, passing data like the recipient number and message content in JSON format. The API handles delivering the message via Sinch's SMS infrastructure.
Dotenv helps secure sensitive credentials like Sinch API keys and service plan IDs. It loads these values from a '.env' file into process.env, keeping them separate from your codebase. This enhances security and avoids accidentally exposing credentials in version control.
For high-volume SMS sending, a message queue like RabbitMQ or Redis is recommended. It decouples API requests from the actual sending process, allowing the server to quickly accept requests and put them on the queue. Background workers then pull messages from the queue and send them via Sinch, improving performance and reliability under heavy load.
Yes, the Sinch SMS API accepts an array of recipient numbers in the 'to' field of the request payload. This lets you send the same SMS message to multiple recipients with a single API call. However, ensure your Sinch account and number are provisioned to send to all intended destinations.
Use a try-catch block around your Axios calls to the Sinch API. Log detailed error information from the error.response, error.request, and error.message properties of the caught error object. Provide informative error messages to the client without exposing sensitive internal details. See the article for examples of enhanced logging and retry strategies.
Input validation is essential to prevent security vulnerabilities and API misuse. Check for missing or invalid fields, enforce correct number formats (E.164), sanitize input to prevent injection attacks, and validate message length to avoid issues. Use robust validation libraries like 'joi' or 'express-validator'.
Use the 'express-rate-limit' middleware to control how many requests a client can make within a specific timeframe. This prevents abuse, protects your Sinch budget, and ensures fair API access. Configure the windowMs and max properties to define the time window and request limits.
E.164 is an international telephone number format that includes a '+' sign followed by the country code and the phone number. It's crucial for Sinch SMS because the API strictly requires numbers in this format. Always ensure all user-provided phone numbers are properly formatted before sending them to the API.
Use logging libraries like Winston or Pino. These tools provide structured logging, allowing you to record details such as timestamp, message, recipient, error codes, and API responses. Configure the logger to write logs to files or output them to the console, offering comprehensive records for debugging and monitoring.
Store Sinch API credentials (SERVICE_PLAN_ID and API_TOKEN) in a .env file. Use the 'dotenv' package to load these variables into process.env at runtime. Never commit the .env file to version control (add it to .gitignore). For production, consider using more secure environment management solutions provided by your deployment platform.
400 errors indicate an issue with the request sent to Sinch. Common causes include incorrect 'from' or 'to' number formatting, missing required fields in the request payload, or an invalid request structure. Check the detailed error message in the Sinch API response for more specific information.
Use the axios-retry library to automatically retry failed Sinch API calls due to transient network issues or server errors. Configure it to retry only on specific error codes (e.g., 5xx) or network errors, and use exponential backoff to increase wait times between retries, improving reliability.
The 'from' field should contain your registered Sinch virtual number. Ensure this number is associated with your Sinch Service Plan ID and is provisioned for sending SMS. Use the E.164 number format for this field as well.