In software development, APIs are the lifeblood of communication between various components of an application. They set the rules for data exchange, ensuring smooth interaction between systems.

In web and mobile development, selecting the right APIs will make or break your app's user experience, performance, and costs.

At Appwrite, we provide an API-agnostic approach, letting developers choose from various types of APIs that are best suited for their needs. There's no one-size-fits-all solution for backend-client communication. The following overview will help you understand each API's pros and cons so you can choose the best option for your product.

REST and modern web communication

What is REST?

Representational State Transfer (REST) is a stateless, request-response protocol that serves as the foundation of data communication on the web. It is simple, widely understood, and supported by virtually all web clients and servers.

Technical details:

• Methods: GET, POST, PUT, DELETE, PATCH, OPTIONS, HEAD

• Status Codes: 1xx (Informational), 2xx (Success), 3xx (Redirection), 4xx (Client Error), 5xx (Server Error) - check out the full list of status codes.

• Headers: Provide metadata (e.g., Content-Type, Authorization, Cache-Control, and more)

• Body: Contains the payload of your data

Client                          Server
  |                               |
  | ------ GET Request -------->  |
  |                               |
  | <------- Response ----------- |
  |                               |

Use cases

1. CRUD operations:

   • Products: Blog platforms, content management systems (CMS), e-commerce sites.

   • Why: REST's architectural style is well-suited for Create, Read, Update, and Delete operations, enabling easy management of resources through standard HTTP methods (GET, POST, PUT, DELETE).

2. Public APIs:

   • Products: Social media platforms, payment gateways, data providers.

   • Why: RESTful APIs are easy to use and widely adopted, making them ideal for exposing functionalities and data to external developers and third-party services.

3. IoT devices:

   • Products: Smart home devices, wearable technology.

   • Why: REST's simplicity and statelessness make it suitable for IoT devices, which often need to send data to and receive commands from a server with minimal overhead.

4. Mobile and web applications:

   • Products: Mobile apps, single-page applications (SPAs).

   • Why: REST APIs allow mobile and web applications to communicate with back-end servers efficiently, fetching data, and performing actions without requiring heavy server-side frameworks.

How Appwrite uses REST

Appwrite uses REST as the primary API for communication between clients and the backend services using the different Appwrite SDKs. All REST API requests in Appwrite are made over HTTP, making it easy to interact with the backend services using standard HTTP methods. Due to the simple nature of HTTP and REST, this is usually the best choice for getting started with Appwrite.

WebSockets: enabling real-time communication

What are WebSockets?

WebSockets provide a full-duplex communication channel over a single, long-lived connection. This protocol allows for real-time data exchange between the client and server, which is essential for applications requiring instant updates, such as chat apps or live notifications.

Technical details:

• Handshake: Starts as an HTTP connection and upgrades to WebSocket

• Communication: Bi-directional, allowing data to be sent and received simultaneously

• Frames: Text and binary frames for data exchange

Client                          Server
  |                               |
  | -- WebSocket handshake --->   |
  | <--- Handshake response --    |
  |                               |
  | <==========================>  |
  |   Bi-directional data flow    |
  |                               |

Use cases

1. Realtime applications:

   • Products: Chat applications, live sports updates, trading platforms.

   • Why: WebSockets' bi-directional communication allows for instant data updates, making it perfect for real-time interactions.

2. Collaborative tools:

   • Products: Online collaborative editors, project management tools.

   • Why: WebSockets enable real-time data synchronization, allowing multiple users to collaborate seamlessly.

3. Live feeds:

   • Products: Social media feeds, live notifications.

   • Why: WebSockets can push updates to clients immediately, ensuring that users receive the latest information without delay.

4. Gaming:

   • Products: Multiplayer online games.

   • Why: WebSockets' low latency and continuous data exchange are crucial for the smooth operation of multiplayer games.

How Appwrite uses WebSockets

Appwrite leverages WebSockets to offer real-time capabilities. For example, when a database entry is updated, a WebSocket connection can notify all subscribed clients of the change in real time. This ensures that users always have the most up-to-date information without needing to refresh the page.

All of the Appwrite client SDKs for Web, Flutter, iOS, or Android come with built-in abstraction for the real-time API, which allows you to easily listen to different channels and register your callbacks.

import { Client } from "appwrite";

const client = new Client()
    .setEndpoint('<https://cloud.appwrite.io/v1>')
    .setProject('<PROJECT_ID>');

client.subscribe('account', response => {
    console.log(response);
});

GraphQL: Efficient data querying

What is GraphQL?

GraphQL is a query language for APIs and a runtime for executing those queries using a defined type system for your data. It allows clients to request exactly the data they need, reducing the amount of data transferred and improving performance.

Technical details:

• Schema: Defines types, queries, mutations, and subscriptions

• Queries: Precise data fetching, multiple resources in a single request

• Mutations: For writing data

• Subscriptions: For real-time updates

Client                          Server
  |                               |
  | ----- GraphQL query --------> |
  | {                             |
  |   user(id: "1") {             |
  |     id                       |
  |     name                     |
  |     email                    |
  |   }                          |
  | }                             |
  |                               |
  | <---- Query response -------- |
  | {                             |
  |   data: {                     |
  |     user: {                   |
  |       id: "1",                |
  |       name: "John Doe",       |
  |       email: "john@example.com"|
  |     }                         |
  |   }                           |
  | }                             |
  |                               |

Use cases

1. Complex data requirements:

   • Products: Data-heavy applications like dashboards, analytics tools.

   • Why: GraphQL enables clients to fetch nested and related data in a single request, reducing the need for multiple round-trips.

2. Microservices architectures:

   • Products: Applications built with a microservices approach.

   • Why: GraphQL can aggregate data from multiple services, providing a unified API for the client.

3. Mobile applications:

   • Products: Mobile apps with varying data needs depending on user interaction.

   • Why: GraphQL allows mobile clients to request only the data they need, reducing bandwidth usage and improving performance.

4. API flexibility:

   • Products: Platforms offering public APIs, SaaS products.

   • Why: GraphQL's flexibility allows developers to evolve their APIs without breaking existing clients, as clients specify their data requirements explicitly.

How Appwrite uses GraphQL

Appwrite supports GraphQL as an alternative to REST for data querying. This enables developers to fetch precisely the data they need, optimizing network usage and improving application performance. GraphQL's flexibility also allows for more complex queries and interactions with the backend. You can use GraphQL to perform multiple operations in a single network request.

The Appwrite GraphQL API is compatible with any standard GraphQL client available for your programming language.

query GetAccount {
    accountGet {
        _id
        email
    }
}

{
    "data": {
        "accountGet": {
            "_id": "...",
            "email": "..."
        }
    }
}

Compare REST vs GraphQL vs WebSockets

Pros and cons

How to choose your API?

Understanding these APIs and protocols for communication is crucial for developers because they are the foundation of most web and mobile apps. Knowing the differences, pros, and cons helps you choose the best one for your needs or combine multiple types of APIs for better performance and user experience.

It's important to remember that starting simple or experimenting can be the best approach. Not every product needs to be perfect from the start; great products evolve and improve over time.

If you’d like to experiment with Appwrite, you can get started here.