For which something like a 4 KB limit is more than enough, like options on a table.

The point is, once you switch from options to actual data, you switch from GET to POST. This is not a bug, this is a feature. POST is for posting data. GET is for retrieving it only, not for sending it.

More than enough in your opinion. It is perhaps your use case that 4KB works completely fine for, but this is not everyones.

We have a fairly complex set of options users can filter through (by design, and prior to its implementation, by high % of requests by users, FWIW) that need to be sharable on the GET request, they are definitely at least 12KB, likely more.

But that's far too large to easily share in things like plaintext emails or text messages.

If you're unable to compress it further, why don't you implement a TinyURL-type scheme? Save the options on your backend and give them a pointer to the settings. And it can expire after 30d or 1y or never.

Then it actually becomes the size of something shareable.

URLs are resource locators. You're not locating a resource, you're passing a gigantic configuration payload.

This is true, but it is the most efficient way that doesn’t induce complexity like having to serialize every option chosen to the backend immediately. Knowing we can re-create everything in first request is much more simple than other methods and doesn’t require the end user to get a special link generated for sharing they can just share straight for the URL bar.

Well there's certainly nothing that strictly prevents GETs from having a body other than no guarantee that all client libraries will handle them. I've seen a mix that allow it and disallow it. What is common is the libraries that don't support it don't seem to have any indication of this and from what I remember are likely to fail silently. Fairly annoying, so it makes sense why this is basically never used.

> Since GET requests aren't suppose to have `body` data, if you have any hope of passing information along to a GET request, you must encode it in the URL in some way.

Or in the request headers.

To be clear, I misspoke, I should have put effectively GET requests really can't have body data. Headers have the same problem. You can't possibly encode it without encoding it in the URL anyway