A chat API (application programming interface) is a modular software component hosted in the cloud that makes it easy for developers to add in-app messaging to any existing web, desktop, or mobile application — or build any type of standalone chat application.

A chat API includes pre-built features and functions that can be integrated by simply pasting and modifying a few lines of code instead of coding the same functionality from scratch.

How Chat APIs Work

Chat API vendors like Stream build, maintain, and consistently update back-end chat infrastructure, and client-side applications interact with this infrastructure to power communication between users. As a modular component within an application’s architecture, the right chat API will essentially plug and play with other app features, existing frameworks, and other SaaS integrations. With the heavy back-end lifting taken care of, a chat API gives developers a proven foundation to build on instead of diverting time and resources to reinvent the wheel.

Software teams turn to these types of cloud-hosted component solutions more and more often because they drastically reduce the time and cost required to build chat while maximizing performance, reliability, and scalability. A chat API minimizes uncertainty and risk in the development process, allowing engineers to stay focused on other mission-critical projects instead of taking the time to research and experiment with chat technology. The chat API serves as an abstraction layer, so a skilled developer can achieve desired results by interacting with it without the need to deeply understand every detail of how it works under the surface.

Parallel Development Processes & Microservices Architecture

Chat APIs are a natural fit for modern development processes and microservices architectures, in which individual features and components are largely self-contained, interacting with each other through a limited number of touchpoints instead of being tightly interwoven. This parallel development approach allows for rapid iteration and near-constant deployment of updates with less danger that an update to one feature will break another feature.

Chat APIs also tend to support multiple back-end frameworks, like PHP, Python, Go, Ruby, Java, JavaScript (Node), and Flutter/Dart. This flexibility ensures that teams can choose to work in the language that makes the most sense given their expertise and their app’s existing tech stack.

Cross-Platform Feature Parity

Competitive apps need to present a consistent user experience across multiple platforms like iOS, Android, web, and desktop. API solutions simplify this development challenge, providing a common backend codebase that a full spectrum of popular frontend languages can interact with. The vendor employs teams of experts to maintain libraries for each platform, so customer organizations don’t need to invest in new engineering talent just to integrate a cross-platform chat feature.

Chat API Use Cases

In-app chat has been proven to boost user engagement and retention across application categories as diverse as telemedicine, banking, education, and ecommerce, while dedicated social messaging apps provide a popular IP-based alternative to traditional text messaging via SMS. Product managers in these fields and beyond prioritize chat functionality as a way to build community, trust, and loyalty around their apps, solve users’ communication challenges, and make it easier for customers to contact sales and support teams. A polished chat experience helps users feel connected and confident so they can focus on important conversations instead of struggling with the technology that powers them.

Chat or messaging functionality can improve outcomes for practically any type of app, but here are several of the most common chat API use cases:

• Social messaging apps like WhatsApp, iMessage, and Facebook Messenger
• Team chat apps like Slack
• Sales and customer support chat apps like Intercom and Drift
• Livestream chat within virtual event platforms
• Patient-provider messaging in telemedicine apps
• Gaming and Esports live chat
• Virtual classroom live chat in education platforms
• Buyer-seller communication in marketplace apps
• Account inquiries and financial guidance in banking and other fintech apps

Chat API Features

Today’s users expect a fast, reliable, feature-rich, and engaging chat/messaging experience across many types of applications. That experience can take months or even years to deliver reliably at scale, but a chat API provides all of the latest features right out of the box. Product teams can choose which chat API features to integrate based on their unique use case and customer needs.

Baseline Chat Feature Requirements

• App registration page and user authentication system
• Message text editing field with keyboard
• Conversation window with sent and received messages clearly distinguished from each other and ordered chronologically
• List of contacts with easy contact import and editing functionality
• Ability to package and send a message
• Ability to receive, interpret, and display a message
• Notifications, unread message counts, and/or message states (read/unread)
• Storage of past messages
• User presence indication (available, away, offline, time last active)

Advanced Chat API Features

Leading chat apps like WhatsApp, iMessage, Facebook Messenger, and Slack continue to innovate, adding features that make it easier, faster, and more fun to send and receive messages. As a result, users already take many of the advanced features below for granted. A worthwhile chat API should include pre-made, customizable versions of each.

• Message reactions let users select a quick response without typing
• Threads visually group replies to a specific message
• AI text and image moderation keeps conversations appropriate when message volume or other factors make human moderation challenging
• URL enrichment shows image, text, and video previews right in the chat window

• @mentions make sure the right people see important messages that might otherwise get buried in a group chat

• Push notifications make sure users receive updates when they’re not actively checking the app

• Flexible permissions allow for admins, moderators, and other user roles needed in some chat use cases
• Slash commands let users interact with other apps right from the chat window
• Media attachments let users share files and view some file types without leaving your app
• Typing indicators keep users engaged while waiting for a reply
• Silent messages are a useful way to distribute information without marking a channel as unread
• Read receipts decrease uncertainty and provide situational context in between messages
• Delivery receipts provide peace of mind for users on unreliable connections
• Language translation connects users across continents and cultures
• Public channels let users form and join communities large and small
• Private channels let users associate with only chosen group members
• CDN storage reduces latency in long-distance communication
• Webhooks let your app send notification texts and emails to offline users and allow for chatbot integrations
• SAML single sign-on (SSO) and multi-factor authentication (MFA) increase authentication security and convenience
• Multi-tenant and team functionality separates unaffiliated groups of users from each other
• View additional advanced chat API features

Chat API Integration Tools & Front-End Components

Many chat APIs come with additional toolkits designed to support front-end integration and help teams achieve desired results. Known as software development kits (SDKs), these toolkits include resources like technical tutorials, code samples and sample apps, and ready-made UI components in familiar front-end languages. Development and design teams can borrow, customize, and deploy these components as desired.

Many chat SDKs come as a complete package with everything needed to build chat for a specific use case like team chat, social messaging, gaming, livestream chat, or sales/customer support. The best chat API solutions will include SDK support for a variety of today’s most popular front-end languages, including Flutter, React, React Native, Javascript, iOS/Swift and Android/Java+Kotlin.

Hands-On Chat API Trials & Free Options

The best way to understand what a chat API is and how it works is by experimenting with one yourself. Many chat APIs offer free trials and interactive code tutorials with their full functionality unrestricted, so engineers can decide through hands-on interaction whether the API will meet their needs and integrate with their app’s existing tech stack. Chat API free trials help fast-track the prototyping and testing process to get a working chat MVP in front of stakeholders and test users as fast as possible without a massive investment of resources up front.

Even aspiring developers and others not working on large commercial projects can benefit from chat API technology — free plans like Stream’s Maker Account make enterprise-grade chat features available to the broader dev community, so anyone can tinker and learn more about how to build chat.