This is a quick post just to let you know that the next version of Proxy.app, which we are planning to release next week with the blessing from Apple, will also contain features that will make working with JSON a breeze.
The JSON support comes in two ways. First we can now render JSON in a formatted view that you can use to explore tree structures with collapsible/expandable nodes. Second, any unicode text that is enclosed will be rendered properly. As you can see from the screenshot above, the last node is rendered "тихо" instead of "\u0442\u0438\u0445\u043e", which in our opinion is a much better representation. Of course you can always go back and preview the original text.
The next version is just going to be awesome and feature pack. Not only we improved the preferences, added a web view for rendering the responses in an actual browser, properly format XML and JSON but also we are shipping with our helper tool which will enable you to auto configure proxy settings and proxy only selected processes.