Introduction to Async APIs

Thu Nov 11 2021

2 min read

APIs let you perform complex business operations by working with both the client and the server. If a human conducts these operations, it will take a lot of time, and also, there will be a considerable margin for error. So you must design your APIs as efficiently as possible because your company’s success may depend on how effectively you have implemented the communication.

There are two kinds of APIs: Synchronous and Asynchronous. Let’s take a look at the latter one.


Before we talk about AsyncAPI, let’s briefly mention Event-Driven Architecture (EDA). The EDA is a software architecture paradigm involving production, detection, consumption, and reaction to events.

AsyncAPI is an open-source project aimed at improving the current state of EDA. These APIs allow relatively time-consuming requests to be processed in the background while other requests are made.

Like the OpenAPI specification, AsyncAPI also provides a specification that allows developers, architects, and product managers to define asynchronous API interfaces. The recently released AsyncAPI specification 2.1.0 laid the foundation for EDA's more significant and better tool ecosystem.

AsyncAPI Document

Like OpenAPI, AsyncAPI also uses a document that contains standardized definitions of channels, subscribers, messages, and payloads. The document file is either a YAML or JSON file.

The payload may include data types, minimum, maximum values, and regexp.

Benefits of Using AsyncAPI

Let’s take a look at some of the advantages of using AsyncAPI over synchronous APIs.

Ready-to-use Tools

AsyncAPI also provides ready-to-use tools to help with the practical implementation of the AsyncAPI standard. Code and documentation generation tools for the most popular platforms make it easier for developers to implement standards in their APIs.

Message Format

Since there is a specification written for the AsyncAPI, there is also a well-defined structure for exchanged messages. The message format needs to be generic so all the participants involved in the communication can understand. AsyncAPI supports multiple schemas like JSON, etc.

Improved Quality of Service for API Consumers

AsyncAPI can generate API documentation with the AsyncAPI document using YAML or JSON. It helps the API consumers to understand how to use your API.

Multiple Protocols

There are different protocols for exchanging data between other APIs. For instance, there are WebSockets, Kafka, etc. But the AsyncAPI standard is expected to be applicable no matter the protocol.