I've been working with API POST requests and I'm trying to decide whether to use application/x-www-form-urlencoded or multipart/form-data in a non-browser, API client context. While it's generally understood that multipart/form-data is necessary for file uploads in browsers, in an API setting the distinction isn't always as clear.
For example, if I'm just sending simple key-value pairs, it seems that application/x-www-form-urlencoded is the go-to. However, if the data includes non-ASCII characters or is binary data, multipart/form-data is suitable.


On the other hand, when I'm dealing with file uploads or need to combine text and binary data, multipart/form-data seems to be the right choice.


Can anyone shed some more light on this topic or share best practices for choosing between the two?

Certainly, when working with APIs, it's important to consider overhead. The multipart/form-data type introduces a lot of overhead compared to application/x-www-form-urlencoded because it needs to include mime type and boundaries. This adds to the size of the request, which can impact performance.