RFC 2068: Section 3.2.1: General Syntax

Note: Servers should be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations may not properly support these lengths.

Okay, so if I’m making a web service call to a particular URI it’s more than likely going to be inside of my own code base as opposed to inside of someone’s client. And in the cases that it’s not chances are pretty good that this same client doesn’t support the extended functionality of my shiny new asynchronous Web 2.x+ app. So whether or not a client supports URI lengths over 255 bytes is probably less of a concern given that these same clients couldn’t support my application in the first place.

But let’s set aside the most likely client-side scenarios and assume nothing: RFC 2068 is about a week shy of being 11 years old. Is the 255 byte URI length recommendation still applicable? From the client perspective, possibly not. But what about from the proxy perspective? And are there clients (possibly mobile browsers?) that I’m not taking into consideration that still impose a limitation on the URI length?

NOTE: As of October 27th, 2007 the limit inside of Internet Explorer is 2083 bytes. Is 2083 bytes today’s equivalent of the 255 byte recommendation of 11 years ago? (You would have to assume that MSFT didn’t arbitrarily arrive at this figure, basing the limitation on known limitations of the existing infrastructure of the Internet, correct?)