HTTP (Hypertext Transfer Protocol) is the standard protocol that enables communication between web browsers and servers by sending requests and receiving responses. It forms the foundation of how data is transferred on the web, making websites, apps, and APIs work seamlessly.<\/p>\n\n\n\n
What is HTTP in Computer Networks?<\/strong><\/h2>\n\n\n\n![\"What](\"https:\/\/www.guvi.in\/blog\/wp-content\/uploads\/2025\/12\/What-is-HTTP-in-Computer-Networks_-1200x630.webp\" "\\"\\"")
<\/figure>\n\n\n\nHTTP in computer networks stands for HyperText Transfer Protocol<\/strong>. In practice, this defines how web clients and servers talk to each other. HTTP was created in the early 1990s by Tim Berners-Lee at CERN as the protocol for the World Wide Web. Its job is to standardize how requests (asking for web resources) and responses (delivering those resources) are formatted and exchanged.<\/p>\n\n\n\n\n- Foundation of the Web:<\/strong> HTTP is the \u201clanguage\u201d of the web. When you open any website, HTTP is almost certainly the protocol under the hood that delivers the page content to your browser.
<\/li>\n\n\n\n- Stateless Protocol:<\/strong> HTTP is stateless<\/strong>, meaning each request the client makes is independent of any previous one. The server does not keep any information (session data) about past requests by the client. For example, if you request the same page twice in a row, the server treats each request anew.<\/li>\n<\/ul>\n\n\n\n
Key Features of HTTP<\/strong><\/h3>\n\n\n\nSome of the basic features that make HTTP work include:<\/p>\n\n\n\n
\n- Client-Server Model:<\/strong> HTTP uses a client\u2013server architecture. The client<\/em> (usually your web browser or an app) initiates requests, and the server<\/em> (hosting the website or API) responds. This clear separation allows browsers and servers to evolve independently.
<\/li>\n\n\n\n- Statelessness:<\/strong> Each HTTP request is independent. The server doesn\u2019t remember previous requests from the same client. (In effect, after each response, the connection can close if not persistent.)
<\/li>\n\n\n\n- Connectionless by Default:<\/strong> In older HTTP versions (like 1.0), each request opened a new TCP connection to the server. HTTP\/1.1 introduced persistent connections (keep-alive), so one TCP connection can handle multiple requests in sequence. <\/li>\n<\/ul>\n\n\n\n
If you are curious on how servers handle requests from HTTP, read the blog – <\/em>How Do Servers Handle Requests? A Comprehensive Guide<\/em><\/a><\/p>\n\n\n\nHow HTTP in Computer Networks Works?<\/strong><\/h2>\n\n\n\n![\"How](\"https:\/\/www.guvi.in\/blog\/wp-content\/uploads\/2025\/12\/How-HTTP-in-Computer-Networks-Works_-1200x630.webp\" "\\"\\"")
<\/figure>\n\n\n\nAt its core, HTTP is simple: a client sends a request and a server sends a response. Here is a step-by-step look at a typical HTTP transaction:<\/p>\n\n\n\n
\n- Client Sends an HTTP Request:<\/strong> You (the client) ask for something. For example, you enter http:\/\/example.com\/index.html in your browser. The browser constructs an HTTP request message<\/strong> that includes a request line<\/em> (with a method like GET, the resource path \/index.html, and the protocol version), headers (like Host: example.com, User-Agent, etc.).
<\/li>\n\n\n\n- Server Processes the Request:<\/strong> The web server receives this request and processes it. It determines which resource is being requested (e.g., the file index.html) and what the client is asking. It may read the file from disk, run scripts, query databases, or perform other logic to prepare a response.
<\/li>\n\n\n\n- Server Sends an HTTP Response:<\/strong> After preparing the data, the server sends back an HTTP response message<\/strong>. This response starts with a status line<\/strong>, for example, HTTP\/1.1 200 OK, indicating success. It then includes response headers (like Content-Type, Content-Length, etc.) and finally the message body (e.g. the HTML<\/a> content of the page). If the requested resource is not found, the server might send 404 Not Found instead.
<\/li>\n\n\n\n- Client Receives and Renders:<\/strong> Your browser (the client) receives the response. It reads the status code: if 200 OK, it proceeds to parse the content. The browser then renders the page for you to see. If the response included references to additional resources (images, CSS<\/a>, scripts), the browser makes additional HTTP requests to fetch those as well, repeating this cycle.<\/li>\n<\/ol>\n\n\n\n
If you want in-depth knowledge about computer networks and don\u2019t know where to start, consider enrolling in HCL GUVI\u2019s Self-Paced Networking Concepts course<\/a>, which covers essential networking concepts, protocols, and security measures to help upskill your career in IT infrastructure and network management.<\/p>\n\n\n\nHTTP Requests and Methods<\/strong><\/h2>\n\n\n\n![\"HTTP](\"https:\/\/www.guvi.in\/blog\/wp-content\/uploads\/2025\/12\/HTTP-Requests-and-Methods-1200x630.webp\" "\\"\\"")
<\/figure>\n\n\n\nAn HTTP request<\/strong> has the following structure:<\/p>\n\n\n\n\n- Request line:<\/strong> Contains the method (action), the resource path (URL), and the HTTP version. e.g. GET \/about.html HTTP\/1.1.
<\/li>\n\n\n\n- Headers:<\/strong> Key-value lines that carry meta-information (like Host:, Accept:, User-Agent:, Authorization:, etc.).
<\/li>\n\n\n\n- Body (optional):<\/strong> Data sent with the request, used by methods like POST or PUT.<\/li>\n<\/ul>\n\n\n\n
The HTTP methods<\/strong> define what action the client wants to perform on the resource. The most common methods are:<\/p>\n\n\n\n\n- GET:<\/strong> Retrieve a resource. For example, GET \/index.html asks the server to send the page content. It should have no side effects (it doesn\u2019t change the server state).
<\/li>\n\n\n\n- POST:<\/strong> Submit data to the server (such as form submission). The request often contains data in the body. The server processes this data (e.g., to create a new record).
<\/li>\n\n\n\n- PUT:<\/strong> Upload or update a resource. This method sends data that should completely replace the target resource.
<\/li>\n\n\n\n- PATCH:<\/strong> Partially modify a resource. Instead of replacing the whole resource like PUT, PATCH applies incremental changes.
<\/li>\n\n\n\n- DELETE:<\/strong> Remove a resource. E.g., DELETE \/user\/123 would ask the server to delete user #123.
<\/li>\n\n\n\n- HEAD:<\/strong> Identical to GET but asks for no message body; useful to check headers\/status (like a lightweight check).
<\/li>\n\n\n\n- OPTIONS:<\/strong> Ask the server which methods and headers are supported for a resource.
<\/li>\n\n\n\n- CONNECT:<\/strong> Establish a tunnel to the server (used by proxies and in HTTPS negotiation).
<\/li>\n\n\n\n- TRACE:<\/strong> Echo the incoming request (used for debugging); rarely used due to security concerns.<\/li>\n<\/ul>\n\n\n\n
These methods are key to HTTP\u2019s flexibility. For example, reading a blog post is done with GET, submitting a login form might use POST, and updating your profile picture could use PUT or POST.<\/p>\n\n\n\n
What are HTTP Status Codes?<\/strong><\/h2>\n\n\n\nWhen the server responds, it always includes a status code<\/strong> (a 3-digit number) that tells the client how the request went. These codes are grouped into five categories:<\/p>\n\n\n\n\n- 1xx (Informational):<\/strong> Request received, continuing process (rarely used).
<\/li>\n\n\n\n- 2xx (Success):<\/strong> The request was successfully received and processed.
\n\n- 200 OK<\/em> \u2013 Standard response for successful GET or POST.
<\/li>\n\n\n\n- 201 Created<\/em> \u2013 A new resource was successfully created (often after a POST).
<\/li>\n\n\n\n- 204 No Content<\/em> \u2013 Request succeeded, but there is no content to return (for DELETE, PUT without response body, etc.).
<\/li>\n<\/ul>\n<\/li>\n\n\n\n- 3xx (Redirection):<\/strong> Further action needed.
\n\n- 301 Moved Permanently<\/em> \u2013 The resource has a new URL.
<\/li>\n\n\n\n- 302 Found<\/em> \u2013 Temporary redirect.
<\/li>\n\n\n\n- 304 Not Modified<\/em> \u2013 Resource not modified; use cached version.
<\/li>\n<\/ul>\n<\/li>\n\n\n\n- 4xx (Client Error):<\/strong> The request was invalid or cannot be fulfilled by the server.
\n\n- 400 Bad Request<\/em> \u2013 Server could not understand the request.
<\/li>\n\n\n\n- 401 Unauthorized<\/em> \u2013 Authentication required or failed.
<\/li>\n\n\n\n- 403 Forbidden<\/em> \u2013 Server refuses to fulfill.
<\/li>\n\n\n\n- 404 Not Found<\/em> \u2013 The requested resource isn\u2019t available on the server.
<\/li>\n\n\n\n- 418 I\u2019m a teapot<\/em> \u2013 (An Easter egg status code from an April Fools joke; rarely seen in practice.)
<\/li>\n<\/ul>\n<\/li>\n\n\n\n- 5xx (Server Error):<\/strong> The server failed to fulfill a valid request.
\n\n- 500 Internal Server Error<\/em> \u2013 General server failure.
<\/li>\n\n\n\n- 502 Bad Gateway<\/em>, 503 Service Unavailable<\/em> \u2013 Server cannot handle request (overloaded or down), etc.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n
For example, if you try to load a page that doesn\u2019t exist, the server will send 404 Not Found<\/strong> along with a \u201cNot Found\u201d page. If a request is successful, you\u2019ll see 200 OK<\/strong>. Web developers use these codes to understand what\u2019s happening in the background.<\/p>\n\n\n\nHTTP vs. HTTPS (Secure HTTP)<\/strong><\/h2>\n\n\n\n![\"HTTP](\"https:\/\/www.guvi.in\/blog\/wp-content\/uploads\/2025\/12\/HTTP-vs.-HTTPS-Secure-HTTP-1200x630.webp\" "\\"\\"")
<\/figure>\n\n\n\nHTTP by itself sends everything in plaintext over the network. This means an attacker sniffing the network could read the contents of requests and responses (including passwords, cookies, etc.). <\/p>\n\n\n\n
To protect privacy and security, HTTPS<\/strong> was introduced. HTTPS means \u201cHTTP over TLS\/SSL\u201d: before any HTTP data is exchanged, the client and server perform an encryption handshake using SSL\/TLS. All subsequent HTTP messages (requests and responses) are then encrypted.<\/p>\n\n\n\nIn practice, HTTPS<\/strong> works almost exactly like HTTP at the protocol level, except the entire TCP<\/a> connection is secured with encryption. The URL starts with https:\/\/ and the default port is 443 (instead of 80). When you visit an HTTPS site, your browser first checks the server\u2019s digital certificate (issued by a trusted authority) to authenticate the server. Once the TLS tunnel is established, your GET and POST data travels encrypted.<\/p>\n\n\n\nToday, HTTPS is so important that browsers and search engines favor HTTPS by default. For example, Google\u2019s search ranking gives a slight boost to HTTPS sites, and browsers show a padlock icon for HTTPS pages. <\/p>\n\n\n\n
HTTP Versions and Evolution<\/strong><\/h2>\n\n\n\nSince its birth, HTTP has evolved in several versions:<\/p>\n\n\n\n
\n- HTTP\/0.9 (1991):<\/strong> The extremely simple and very first version. It only supported the GET method and had no headers or status codes.
<\/li>\n\n\n\n- HTTP\/1.0 (1996):<\/strong> Introduced headers (like Host, User-Agent) and status codes. Each request still opened a new connection (no reuse).
<\/li>\n\n\n\n- HTTP\/1.1 (1999):<\/strong> Became the dominant standard. It added persistent connections (so multiple requests could reuse one TCP connection), pipelining (sending multiple requests without waiting for each response), chunked transfers, more methods and headers, and caching controls.
<\/li>\n\n\n\n- HTTP\/2 (2015):<\/strong> A major update that keeps the same basic semantics (methods, status codes, URIs) but changes the underlying format to be more efficient. HTTP\/2 is binary instead of text, allows multiplexing many requests\/responses over one connection, uses header compression, and supports server push.
<\/li>\n\n\n\n- HTTP\/3 (2022):<\/strong> The newest version, which uses QUIC<\/a> (a UDP-based transport) instead of TCP. HTTP\/3 offers lower latency and faster page loads in many cases. It integrates encryption and can recover from packet loss faster than TCP. It\u2019s already supported by most browsers and servers.<\/li>\n<\/ul>\n\n\n\n\ud83d\udca1 Did You Know?<\/strong>
The original version of HTTP, called HTTP\/0.9, only supported one command: GET, and it didn\u2019t even include headers or status codes. It was so minimal that every response was just raw HTML with no metadata. Fast forward to today, and we have HTTP\/3 running over QUIC, enabling faster, more reliable connections even on spotty networks like mobile or Wi-Fi.
<\/div>\n\n\n\n<\/p>\n\n\n\n
<\/figure>\n\n\n\nHTTP in computer networks stands for HyperText Transfer Protocol<\/strong>. In practice, this defines how web clients and servers talk to each other. HTTP was created in the early 1990s by Tim Berners-Lee at CERN as the protocol for the World Wide Web. Its job is to standardize how requests (asking for web resources) and responses (delivering those resources) are formatted and exchanged.<\/p>\n\n\n\n Some of the basic features that make HTTP work include:<\/p>\n\n\n\n If you are curious on how servers handle requests from HTTP, read the blog – <\/em>How Do Servers Handle Requests? A Comprehensive Guide<\/em><\/a><\/p>\n\n\n\n At its core, HTTP is simple: a client sends a request and a server sends a response. Here is a step-by-step look at a typical HTTP transaction:<\/p>\n\n\n\n If you want in-depth knowledge about computer networks and don\u2019t know where to start, consider enrolling in HCL GUVI\u2019s Self-Paced Networking Concepts course<\/a>, which covers essential networking concepts, protocols, and security measures to help upskill your career in IT infrastructure and network management.<\/p>\n\n\n\n An HTTP request<\/strong> has the following structure:<\/p>\n\n\n\n The HTTP methods<\/strong> define what action the client wants to perform on the resource. The most common methods are:<\/p>\n\n\n\n These methods are key to HTTP\u2019s flexibility. For example, reading a blog post is done with GET, submitting a login form might use POST, and updating your profile picture could use PUT or POST.<\/p>\n\n\n\n When the server responds, it always includes a status code<\/strong> (a 3-digit number) that tells the client how the request went. These codes are grouped into five categories:<\/p>\n\n\n\n For example, if you try to load a page that doesn\u2019t exist, the server will send 404 Not Found<\/strong> along with a \u201cNot Found\u201d page. If a request is successful, you\u2019ll see 200 OK<\/strong>. Web developers use these codes to understand what\u2019s happening in the background.<\/p>\n\n\n\n HTTP by itself sends everything in plaintext over the network. This means an attacker sniffing the network could read the contents of requests and responses (including passwords, cookies, etc.). <\/p>\n\n\n\n To protect privacy and security, HTTPS<\/strong> was introduced. HTTPS means \u201cHTTP over TLS\/SSL\u201d: before any HTTP data is exchanged, the client and server perform an encryption handshake using SSL\/TLS. All subsequent HTTP messages (requests and responses) are then encrypted.<\/p>\n\n\n\n In practice, HTTPS<\/strong> works almost exactly like HTTP at the protocol level, except the entire TCP<\/a> connection is secured with encryption. The URL starts with https:\/\/ and the default port is 443 (instead of 80). When you visit an HTTPS site, your browser first checks the server\u2019s digital certificate (issued by a trusted authority) to authenticate the server. Once the TLS tunnel is established, your GET and POST data travels encrypted.<\/p>\n\n\n\n Today, HTTPS is so important that browsers and search engines favor HTTPS by default. For example, Google\u2019s search ranking gives a slight boost to HTTPS sites, and browsers show a padlock icon for HTTPS pages. <\/p>\n\n\n\n Since its birth, HTTP has evolved in several versions:<\/p>\n\n\n\n <\/p>\n\n\n\n\n
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<\/li>\n\n\n\nWhat are HTTP Status Codes?<\/strong><\/h2>\n\n\n\n
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<\/li>\n\n\n\nHTTP vs. HTTPS (Secure HTTP)<\/strong><\/h2>\n\n\n\n
<\/figure>\n\n\n\nHTTP Versions and Evolution<\/strong><\/h2>\n\n\n\n
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The original version of HTTP, called HTTP\/0.9, only supported one command: GET, and it didn\u2019t even include headers or status codes. It was so minimal that every response was just raw HTML with no metadata. Fast forward to today, and we have HTTP\/3 running over QUIC, enabling faster, more reliable connections even on spotty networks like mobile or Wi-Fi.
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