HTTP Headers

HTTP headers are key-value pairs that are sent in HTTP requests and responses. They provide information about the request or response, such as the content type, encoding, and caching directives.

Types of HTTP Headers

  • Request Headers: Provide information about the client's request to the server. Examples include User-Agent, Accept, and Authorization.
  • Response Headers: Provide information about the server's response to the client. Examples include Content-Type, Content-Length, and Cache-Control.
  • General Headers: Apply to both requests and responses. Examples include Date and Connection.
  • Entity Headers: Provide information about the body of the request or response. Examples include Content-Length and Content-Encoding.

Common HTTP Headers

Request Headers

  • User-Agent: Identifies the client software making the request.
  • Accept: Specifies the acceptable media types for the response.
  • Accept-Language: Specifies the preferred languages for the response.
  • Authorization: Contains credentials to authenticate the client with the server.

Response Headers

  • Content-Type: Indicates the media type of the response body.
  • Content-Length: Indicates the size of the response body in bytes.
  • Cache-Control: Specifies caching directives for the response.
  • Set-Cookie: Sends a cookie from the server to the client.

Importance of HTTP Headers

HTTP headers play a crucial role in web communication by providing essential information for both the client and the server. They enable features such as content negotiation, caching, authentication, and more. Understanding HTTP headers is essential for web developers to build efficient and secure web applications.