Can/should I use YAML as payload in RESTful webservice?

Question

As the header says.

In general I like YAML more than JSON these days. I implemented a RESTful WS PoC back in the day using JSON. I was wondering if I can instead use YAML or not.

E.g. are there enough tools/libraries/support for doing that? Or would I end up doing quite a bit of mundane/tedious coding which I would've avoided if I were using JSON instead?

Also as I understood from WWW: REST doesn't restrict one from using YAML as the payload, is that correct?

Thanks!