REST payload max size?

We are thinking of using a REST interface for communication between internal apps. App A will have to pass a fair bit of data representing a financial portfolio to app B. Is there any limit to the amount of data that can be passed using a REST API given that REST is implemented using HTTP? I wasn't sure if another protocol (ie: RMI) should be used with a large data set.

No, it's pretty much up to the server implementation if there's any such limit.

There's a limit on the size of a URL (if you wish to put large amounts of data on the URL, like with a GET), but no defined limit for a POST or PUT.

As Will Hartung said, there is no limit in the standard (RFC 2616). But every implementation has its own limits. A few examples:

• Two megabytes for Tomcat (you can change it with maxPostSize)
• Two megabytes for PHP (you can change it with post_max_size)
• Two megabytes for Apache itself (you can change it with LimitRequestBody)

These implementation limits are usually just the default configuration values, and can be changed to larger ones if required.