Is there a maximum size for content of an HTTP POST?

Is there a maximum size for an HTTP POST? And if there is a max size, is it determined by the protocol or is it at the discretion of the server?

The HTTP specification doesn't impose a specific size limit for posts. They will usually be limited by either the web server or the programming technology used to process the form submission.

No limit by specification. The limit is MIN(browser_limit,server_limit).

POST method does not have any limit on the size of data. But Server & Browsers has.

For Example

IE: 2GB
Firefox: 2GB
Chrome: 4 GB
Opera: 4 GB

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https://www.motobit.com/help/scptutl/pa98.htm

I don't think that there is a specific limit in the protocol, BUT there are cases where things get squirrelly if you're transferring huge files. It depends on the size of the file as to what may work a little better for your specific case. There's not any support for checking that the file wasn't corrupted in transfer, for example, unlike using something like a torrent for the transfer.