Where would I find the payload with a Wix webhook?

I have a couple Wix webhooks pointed to a couple routes on my server. The webhook is in fact hitting my routes, but I'm not seeing the payload anywhere. The documentation says it's in the form of a JWT sent in the body of the request. The body is empty though. Am I missing something?

Here is my route receiving the request:

router.post("/app-installed", (req, res) => {
  console.log("req.body: ", req.body);
  console.log("headers", req.headers);
  res.sendStatus(200);
});