Understanding APIs

• Definition: API stands for Application Programming Interface.

• General Term: Broadly used to describe any type of programming interface.

• Many kinds, include:

  • Local Storage API
    • Example: Storing user preferences for themes on YouTube
  • Object-Oriented Programming API
    • Creating an object and defining its interface (methods to access data) is technically an API

  Common API Types

  1. REST APIs
  2. GraphQL APIs
  3. gRPC APIs

REST APIs

Definition:

Stands for Representational State Transfer

• REST APIs are built on the top of HTTP, but REST is not a protocol but a set of restrictions/guidelines applied to HTTP APIs
• Commonly used and aligned with HTTP methods (GET, POST, etc.)

Key Characteristics

Stateless

• Each request from a client to a server must contain all the information needed to understand and process the request
  • No Client Context Stored on the Server: Each request is independent and unrelated to previous requests.
• Examples of Stateless & Stateful (Video Listing on YouTube:)
  • Stateful Example: Server tracks the user's session and knows which videos the user has already seen.
  • Stateless Implementation: Client sends pagination information with each request.
    • First Request: GET /videos?offset=0&limit=10 Start from the 1st video, and fetch the next 10 videos.
    • Next Request: GET /videos?offset=10&limit=10 Start from the 11th video, and fetch the next 10 videos.
    • Query Parameters: offset and limit are used to manage pagination without storing user-specific data on the server.
• what is pagination?
  • Technique to manage large sets of data by dividing them into discrete pages
    • URL Parameters:
      • Offset: Indicates where to start fetching the next set of data
      • Limit: Indicates the number of items to fetch
      • Example URL: youtube.com/videos?offset=10&limit=10,Fetches the next 10 videos, starting from the 11th video

• Benefits of Statelessness