All about messaging API’s

By: Chris Keys

What is a Messaging API?

Let’s start with a bigger question…”What is an API?”. Well API stands for Application Programming Interface, which itself may not help much!


Think of two computer systems trying to “talk” to each other – perhaps your company’s marketing CRM system and our Viber Business Messaging system. 


If your marketing system wants to send a Viber message to a customer, it needs to give instructions to our system to tell it: what content to send, to which mobile number, what to do if it can’t deliver on Viber, and finally from what business name. Later on your system will want to be told if the message was delivered properly. 


API is the term programmers use to define the method, content and format of the communications between the two systems. It includes rules and codes such as network addresses, security rules, speed of sending, available credit balance etc. Put all that together and you have an API!

Why and When should you use a Messaging API?

When you have messages generated by a system – such as a one time password, a package delivery notification, a credit limit exceeded message – it makes sense to send those “transactional” messages without a human getting in the way! This is the classic use for a Messaging API.


That is not to say it is the only time. Some companies generate marketing traffic, for example from a CRM system, such as Salesforce, and send that out using API.

How can I use an API to send One Time Passwords?

One Time Passwords (OTP) are perhaps the most common use of Messaging API’s. An end customer using your website or mobile app requests an OTP, the password is sent through a Messaging API and the end customer receives an SMS and types the password into your app – proving they are in possession of the mobile number.


Some messaging providers such as Promotexter provide this as a complete service. First your system calls the API to generate and send an OTP code by SMS to your customer. Then you call the API again to validate the OTP that  the customer entered into your app.


Increasingly, companies are looking at alternatives to sending OTP via SMS, such as sending via Viber which is faster and more secure.

Chat using an API?

Messaging APIs can handle inbound messages as well as outbound. This allows you to integrate inbound messages to your CRM system or to build 2-way chat solutions without having to worry about message delivery – just leave that to the API provider.

Security and Privacy

Most API providers now insist on secure connections. Make sure when choosing a provider they offer secure messaging (at least TLS 1.2) and ideally IP whitelisting. You should also be sure you can trust the provider to secure your messaging data in their servers – ensure they have a Privacy Policy that meets your needs based on your local laws.


Given you need a service that stays up, ensure the provider is hosted on a secure reputable cloud, such as Amazon Web Services, Google Cloud or Microsoft Azure, with proper redundancy, scalability and business continuity planning in place.

Getting Started

If you’re ready to get started, some providers will let you create a free trial account. You should review their API documentation and be sure it meets your needs before committing further.


Check out Promotexter’s SMS, Viber and Email Messaging API functionality by signing up for a free trial account at https://portal.promotexter.com/signup and reviewing their API docs online at https://promotexter.docs.apiary.io/#

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