is there a callout.received.content.length?

[b2d5]

The reliable way of checking the request/response sizes are client.received.content.length/target.received.content.length (which don't appear in the flow variables reference document), because content-length headers are not fully reliable. In the case of a service callout, is there equivalent sent/received/port/state/etc. variables?

[cjking]

Not exposed as an existing flow variable like this. You'd probably need to read the contents into a JS policy, compute a string length on the results and write the results to another flow variable.