Requirements of the Messenger API

Introduction to Messenger

Instant messaging applications, such as Messenger, WhatsApp, and Telegram, connect millions of people who share billions of messages daily. These applications utilize the latest technologies to efficiently handle a large number of users and messages via their extensive API. To understand the working of these APIs, let's design an API for Facebook Messenger. We need to determine what services the Messenger API utilizes and how the interaction occurs between them to assist real-time chat. Before we dive deep into the design of the Messenger API, we will identify requirements and focus on the workflow that takes place via the interacting entities.

We’ll start our discussion by identifying the important requirements for the Messenger API.

Requirements

To design API for Messenger, we will focus on the following functional and non-functional requirements:

Functional requirements