What Content-Type types are permissible when sending HTTP requests?

When sending HTTP requests, the Content-Type header specifies the type of the request body content. The most common types:

• application/json — for transmitting data in JSON format.
• application/x-www-form-urlencoded — for transmitting form data in URL encoding.
• multipart/form-data — for transmitting files and form data.
• text/plain — plain text.
• application/xml or text/xml — for XML data.

The choice depends on the data format the server expects. For example, REST APIs most often use application/json.

Example of setting Content-Type in Java using HttpURLConnection:

connection.setRequestProperty("Content-Type", "application/json");