Understanding the Differences Between HTTP GET and POST Methods

GET and POST are the two basic HTTP request methods, and anyone who has done web development can name several differences between them.

The most obvious difference is that GET puts parameters in the URL while POST sends them in the request body.

Typical interview answers list the following distinctions:

GET is harmless when the browser goes back, whereas POST may resubmit the request.

GET URLs can be bookmarked; POST URLs cannot.

GET requests are cached by browsers by default, POST requests are not unless manually configured.

GET only supports URL‑encoded data, while POST supports many encoding types.

GET parameters remain in the browser history; POST parameters do not.

GET URLs have length limits (usually around 2 KB in browsers), while POST has no practical limit.

GET accepts only ASCII characters; POST has no such restriction.

GET is less secure because parameters are exposed in the URL, making it unsuitable for sensitive data.

GET passes parameters via the URL, POST passes them via the request body.

(The standard answer is referenced from w3schools.)

In reality, both GET and POST operate over the same TCP connection; the protocol itself does not differentiate their capabilities. The differences arise from HTTP specifications and the practical limits imposed by browsers and servers.

TCP is like a reliable delivery truck. HTTP defines service categories such as GET, POST, PUT, DELETE, etc. When a GET request is made, the data is placed on the truck’s roof (the URL) for easy recording; a POST request puts the data inside the truck’s cargo area.

Although you could technically hide data in the cargo area of a GET request or on the roof of a POST request, doing so violates the intended semantics of the methods.

Browser and server implementations impose limits on URL length—most browsers cap URLs at about 2 KB, and many servers reject URLs larger than roughly 64 KB. Exceeding these limits leads to request failure.

Another practical difference is the number of TCP packets exchanged: a GET request typically sends the HTTP header and data in a single packet, receiving a single 200 OK response; a POST request often follows a two‑step handshake where the client sends the header, the server replies with a 100 Continue, and then the client sends the body, resulting in two packets.

Because POST involves an extra round‑trip, it can be slightly slower, especially on poor network conditions, though modern browsers like Firefox may optimize this to a single packet.

When interviewers ask about GET vs POST, remember that while the underlying TCP transport is the same, HTTP rules, browser/server limits, caching behavior, and security considerations create observable differences that guide proper usage.