Webhook payload example (using workflow)


Hi, I am doing some integration test with webhook and workflow and reading through the doc, I couldn’t find couple of things and hoping the community could help me out. It says, the payload could be in batches but I didn’t find any example and I did some test and I wasn’t able to create a batch payload. Anyone have any example?
Also, is there any spec for contact events? like field length and such? Thank you in advance for any help.