I am using
Ajax Toolkit function
sforce.connection.remoteFunction. What are the limitations of this method? For example if I send an encoded Blob content as a request, is there any limitation on the size of the request I send?
I've never managed to hit the limits on this function, and not for a lack of trying. I've written scripts on my personal server that returned payloads in the hundreds of megabytes, and the proxy worked just fine. I've also posted hundreds of megabytes of data in a single call.
As far as I know, there's no documentation on what limits exist, other than the fact that hosts must be on certain ports (80, 443, or 1024-65535), and that port 80 and 443 only allow insecure and secure connections (respectively), and hosts must be pre-configured by administrators to allow access. Of course, doing things that break the normal rules of HTTP may not be supported, such as using an unknown HTTP verb.