Requirements of the Chat Application

Chat applications are among the most widely used digital services, powering everything from casual conversations to enterprise communication. Apps like WhatsApp, Facebook Messenger, Slack, and Discord have transformed how we interact, enabling instant, persistent, and asynchronous messaging worldwide. But while the user experience appears seamless, the underlying frontend System Design is incredibly complex.

The challenge is ensuring real-time communication, instant feedbackInstant feedback includes message delivery statuses such as sent, delivered, read, etc., high availability, and smooth performance across multiple devices, networks, and geographies.

In this lesson, we will examine the fundamental requirements of a modern chat frontend system, explore the challenges we can face while designing, and outline the prerequisites to design a high-performance chat frontend system.

Let’s start with the requirements!

Requirements

At its core, a chat application allows users to exchange messages instantly over a network. While text-based messaging forms the foundation, modern chat systems offer voice messages, video calls, multimedia sharing, read receipts, encryption, and group conversations. We should understand the requirements that drive the chat system to design its frontend.

Let’s start with the functional requirements.

Functional requirements

• Instant messaging: The system should allow users to send and receive real-time text messages for ...