The contents of the parcel
Think of a parcel: its label says where it should go, while its contents are the payload. When you order through an app, the request’s payload might contain your items and delivery address. The response’s payload might contain your order number. Headers carry details about how to handle the data.
Payloads can be text, images, files, or sets of details. In a web request, the payload is often called the body. Some requests have no body.
Check what arrives
Apps should check incoming payloads before acting on them and avoid sending personal or secret details they do not need.