Types of API

1. SOAP (Simple Object Access Protocol)

• What it is: SOAP is a protocol for exchanging structured information in the form of XML. It was designed for high-level security and reliability.

• How it works: SOAP uses XML to send messages and relies on specific protocols like HTTP or SMTP for communication.

• Key features:

  • High security (used in banking systems).

  • Strong error handling.

  • Built-in standards (for security, addressing, etc.).

• Real-world use case: Banking systems where secure communication and transactions are essential (e.g., transferring money between banks securely).

2. REST (Representational State Transfer)

• What it is: REST is an architectural style for APIs that use HTTP requests to perform operations (GET, POST, PUT, DELETE).

• How it works: REST sends and receives data as JSON, XML, or other formats, but JSON is most common.

• Key features:

  • Lightweight and fast.

  • Stateless (no session is maintained between requests).

  • Can work with different types of data (like JSON).

• Real-world use case: Social media apps (e.g., when you post a tweet, the app makes a POST request, and when you read tweets, it makes a GET request).

3. GraphQL

• What it is: GraphQL is a query language for APIs that allows clients to request exactly the data they need, making it more efficient than REST.

• How it works: Clients define the structure of the response, which reduces the number of requests (unlike REST where multiple endpoints might be needed).

• Key features:

  • Allows clients to ask for specific fields (no over-fetching or under-fetching data).

  • Single endpoint for all operations.

  • Efficient for complex queries.

• Real-world use case: GitHub API uses GraphQL. Developers can query only the specific details of repositories they need, like name, description, or stars count.

  

4. gRPC (gRPC Remote Procedure Call)

• What it is: gRPC is an open-source RPC framework that allows services to directly communicate with each other in different languages (e.g., Python calling a service written in Go).

• How it works: It uses protocol buffers (protobufs) for defining services and methods, and sends binary data, making it super fast.

• Key features:

  • High performance (better than JSON-based REST).

  • Supports bi-directional streaming.

  • Strong typing (thanks to protobufs).

• Real-world use case: Microservices in large applications (e.g., Google uses gRPC internally for its services where speed is crucial).

• Video Link

5. Webhook

• What it is: A webhook is an API concept where a server automatically sends data to another server when a certain event happens.

• How it works: When an event occurs (e.g., a payment is made), the originating server sends an HTTP POST request to a predefined URL to notify the other system.

• Key features:

  • Event-driven (data is sent when something happens).

  • Efficient for notifications (instead of constantly checking).

• Real-world use case: Payment processing (e.g., Stripe uses webhooks to notify your system when a payment succeeds).

6. WebSocket

• What it is: WebSocket is a communication protocol that provides full-duplex communication, meaning both client and server can send data to each other simultaneously.

• How it works: Once a WebSocket connection is established, messages can be sent and received in real time without reopening the connection (unlike HTTP which needs to open/close with each request).

• Key features:

  • Real-time, two-way communication.

  • Persistent connection between client and server.

• Real-world use case: Online chat applications (e.g., Facebook Messenger or Slack where messages are sent and received in real time without refreshing the page).

Summary Table:

Each of these APIs has its own strengths depending on the use case, so selecting the right one depends on the specific requirements of the system you're building.

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Resources

Top 6 Most Popular API Architecture Styles

Why you should NOT use GraphQL as a backend developer?

tRPC, gRPC, GraphQL or REST: when to use what?

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