Learn how to send and validate one-time passcodes (OTPs) sent to a user's phone via SMS or voice. OTPs are a useful and easy to deploy security tool for initial phone verification at sign up, ongoing login verification with two-factor authentication (2FA), transaction verification, and more. Twilio's Verify API is a purpose-built solution for sending OTPs with the same global reliability and unparalleled delivery at scale as Twilio's programmable messaging with the added benefits of regulatory and compliance management, managed sending phone number pool included, stateless API for handling token generation and checking, templatized OTP message translations in dozens of languages, and more.

Appointment reminders allow you to automate the process of reaching out to your customers in advance of an upcoming appointment. Twilio customers like Handy and Arkansas Children's Hospital use appointment reminders to reduce no-shows and ensure customers have everything they need in advance of an appointment. Whether you're a dentist, doctor, cable company, or car repair shop, you can use automated appointment reminders to save time and money.

In this tutorial, you'll learn how to implement appointment reminders at the moment the appointment is created.

With Twilio's Programmable Chat API you can quickly build custom chat applications. Programmable Chat enables your business to interact with customers and coordinate teams in real time in the web and native mobile applications you're already building. In this tutorial, we'll show you a simple application that allows anonymous users to instantly join and create their own channels.

Create a seamless customer service experience by assigning callers to specialized agents within your call center. With Twilio TaskRouter, you no longer have to handle the complicated task workflow features necessary to build a dynamic call center. Learn how in this tutorial.

Create a seamless customer service experience by building an IVR Phone Tree for your company. IVR systems allow your customers to access the people and information they need. With Twilio, it's easy to build one yourself in the web programming language you already use. Learn how in this tutorial.

In this guide, we'll show you how to use Programmable Voice to make outbound phone calls from your applications.

Allow your customers or mobile employees to call or text each other while masking their phone numbers. By implementing masked phone numbers you can track all conversation metadata in your system while maintaining your customers' privacy. Twilio customers like Uber & Airbnb use masked phone numbers to create a frictionless conversation.

In this tutorial, we'll learn how a company like Airbnb might implement masked phone numbers.

You know how to receive and reply to incoming SMS messages. What if you receive an MMS message containing an image you’d like to download? Let’s learn how we can grab that image and any other incoming MMS media

In this guide, we'll show you how to use Programmable SMS to respond to incoming SMS messages in your web application. Code on your server can decide what happens when someone texts the number you've bought or ported to Twilio.

In this guide, we'll show you how to use Programmable Voice to respond to incoming phone calls in your web application.

In this guide, we'll show you how to use Programmable SMS to send SMS and MMS messages in your application.

Learn how to send media messages with the Twilio API for WhatsApp. Add media attachments like images, audio files, and PDFs to WhatsApp messages with Twilio.

In this guide, we’ll cover how to set up your development environment for a new project in your favorite programming language. We’ll also talk about a couple of helpful tools that we recommend when developing any applications that use Twilio.

Use reserved Twilio numbers to test your SMS application.

By using Twilio as a communication channel your company can reduce the cost of interacting with your customer. Twilio customers like Duke University have automated their workflows to increase engagement and reduce the difficulty for customers. By pairing SMS notifications with inbound SMS handling, your application can be updated from anywhere in the world, by anyone with a phone.

In this tutorial, we'll learn how a company like Airbnb might implement workflow automation to handle reservations.