Popular API Architectures and patterns

| By:
Jon Kenoyer

Application programming interfaces (APIs) are crucial in connecting various software applications, enabling data exchange, and building complex software systems. Selecting the right API architecture style is crucial for developing scalable, flexible, and maintainable software platforms. In this blog, we will walk through different API architecture styles and patterns, and techniques.

There are various API architecture styles that are widely used: RESTful, GraphQL, gRPC, WebSocket, and Webhook.


RESTful API architecture is a popular and widely used approach to designing APIs for web-based applications. It stands for Representational State Transfer and is based on the HTTP protocol.

Benefits of RESTful API architecture

  1. Simplicity: It uses the standard HTTP methods: GET, POST, PUT, and DELETE to perform operations on entities, and it can return responses in a standard format such as JSON or XML. The reliance on standard verbs simplifies the implementation for engineers.

  2. Caching: Since RESTful API architecture relies on HTTP protocol, it allows for caching of responses, which can drastically affect performance and reduce server load for certain use cases.

When to use RESTful API architecture

RESTful architecture is a defacto standard way for simple operations. This provides a simplified and standardized way to perform these operations. RESTful architecture works as well for stateless applications, where each request has all the required information to process the request


GraphQL is an API query language designed to allow clients to pick and choose and request the data which is needed.

Benefits of GraphQL

  1. Efficiency: GraphQL allows clients to specify what data they need, which reduces the amount of data that needs to be transferred over the network.

  2. Versatility: It enables clients to efficiently retrieve multiple resources in a single request. It also provides the flexibility to query data based on specific conditions, such as filtering, sorting, and pagination requirements.

When to use GraphQL

GraphQL is ideal for applications with complex data requirements, where clients need to fetch data from multiple resources and need to access nested data structures along with filtering, sorting, and picking and choosing fields they need.

It also proves to be a practical solution for applications with APIs that undergo frequent changes, where adding or removing fields can disrupt client applications. The schema and type system offered by GraphQL facilitate the evolution of an API without causing disruptions to clients, simplifying the process of maintaining backward compatibility.


gRPC is an advanced, high-performance architecture designed by Google for building large-scale distributed applications. It leverages Protocol Buffers (Protobuf) for efficient serialization and communication. Protobuf is a compact messaging format that enables fast delivery of responses.

Moreover, it enhances message transmission speed between systems by performing the marshaling of message packets, effectively packing parameters and remote functions into binary message packets before sending them over the network.

Benefits of gRPC

  1. High performance: gRPC uses Protocol Buffers, which is a highly packed messaging format for serialization. This allows for faster and more efficient communication between services.

  2. Scalability: It’s designed with scalability in mind to handle many concurrent requests, which is ideal for applications that experience high levels of traffic and require low latency response times.

When to use gRPC

gRPC is the preferred option for developing lightweight microservice applications because it reduces latency and enables faster data transmission. It is particularly well-suited for real-time message delivery in microservices prioritizing efficient and high-speed message serialization. gRPC is especially valuable when connecting systems that rely on lightweight messaging, operate in low-power networks, and prioritize overall efficiency.


WebSocket enables bidirectional, real-time communication between servers and clients in web applications. Unlike traditional HTTP, both the client and server can initiate requests in WebSocket.

Benefits of WebSocket

  1. Two-way communication: WebSocket allows two-way communication between server and client, allowing to exchange and transfer data as soon it is available.
  2. Reduced server load: With traditional APIs, clients have to make repetitive requests to the server at scheduled intervals to check for data updates. This approach often leads to unnecessary server load, and determining the optimal polling frequency can be challenging.

When to use WebSocket

WebSocket is a great choice for event-driven architectures from both client and server perspectives. It removes the limitations of the traditional HTTP lifecycle.


Webhooks allow applications to notify clients when data is available. It enables the server to send information to clients in the standard HTTP protocol.

Benefits of Webhooks                                                          

  1. Event-driven real-time push: Webhooks allow the server to notify the client of changes or provide updates whenever new data becomes available, or events occur. This can be especially useful for applications that require up-to-date information, such as stock market data or social media feeds.

  2. Reduced server load: Webhooks can send updates as they are available, simplifying the implementation.

When to use Webhooks

Webhooks are also a great choice for event-driven architectures, where certain events trigger specific actions. In cases where it makes sense for the server to notify the client, webhooks are the best choice.

Choosing the right API architecture style is crucial to address a specific problem. A one-size-fits-all approach doesn't work when designing a platform, as it may require a combination of different patterns to achieve the desired goals.

API architectures in ConnectWise Asio™

REST is the cornerstone of ConnectWise Asio API architecture because almost all services use that as their public-facing API. A key concept of a microservice architecture is that a service does not allow other services direct database access since that introduces a tight coupling between those services. Due to REST being the most common and easily understood standard and having comprehensive tooling such as OpenAPI (Swagger), almost all services, internal and external, have a REST interface.

In a microservice architecture, GraphQL within Asio addresses two key challenges. Firstly, it enables efficient retrieval of data from multiple sources. Secondly, it facilitates the seamless integration or "stitching" of this data, particularly when considering client browser UI or mobile applications.

It also allows rapid UI development since the UI team is no longer dependent on back-end changes to query data in new ways. Asio operates at scale, with tens of thousands of partners worldwide performing millions of requests every day. gRPC is the tool that allows Asio internal services to communicate efficiently in critical hot spots.

WebSockets in Asio allow UI push notifications, so partners are notified in real-time of events without having to wait for a long-running service to respond. Webhooks, on the other hand, allow safe public third-party access to Asio event streams while still allowing us to implement security and throttling around that access point. Webhooks also help with reliability since integrations no longer have to constantly poll an API to detect a change.