6 GET vs. POST

With our basic {plumber} API, we can make a new endpoint that will grab the raw Goodreads data from Google Sheets, clean it up, and spit it out as JSON that we can use wherever we want.

But first, some quick notes about some internet infrastructure stuff. In the ongoing example, we have two endpoints:

#* Plot a fancy histogram
#* @get /plot
function(n = 100) {
  # STUFF HERE
}

#* Return clean penguins data
#* @get /penguins
function() {
  # STUFF HERE
}

Both of them use @get to create GET endpoints. This means that you can access them directly from a URL.

In general, there are two common ways to send HTTP requests: GET and POST.¹ Here’s my oversimplified mental model for how these two methods work:

Method	How it works	Example	When you’d use it
GET	Any parameters passed to the server appear in the URL	`http://localhost:6312/plot?n=500`	All over the place. You see these all the time. Whenever you see things that look like variables in a URL (like `whatever.com/blah?thing1=5&thing2=10`) it’s a GET request.
POST	Any parameters passed to the server appear behind the scenes	`http://localhost:6312/login` with parameters included in the body of the request	Login forms, anything else where you don’t want sensitive information to be publicly viewable or logged. You can’t really make these requests with just a URL.

Simplified tl;dr

Use GET when you’re passing non-sensitive things to the server.

Use POST when you’re passing sensitive things to the server.