Three binary encodings for JavaScript Object Notation (JSON) are presented. JSON-B (Binary) is a strict superset of the JSON encoding that permits efficient binary encoding of intrinsic JavaScript data types. JSON-C (Compact) is a strict superset of JSON-B that supports compact representation of repeated data strings with short numeric codes. JSON-D (Data) supports additional binary data types for integer and floating-point representations for use in scientific applications where conversion between binary and decimal representations would cause a loss of precision. This document is also available online at http://mathmesh.com/Documents/draft-hallambaker-jsonbcd.html.