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Protocols

CBOR

Concise Binary Object Representation, an IETF binary format with the JSON data model but far smaller encoding, designed for constrained devices and protocols.

CBOR, specified in RFC 8949, encodes the same kinds of values as JSON, objects, arrays, strings, numbers and booleans, plus byte strings and tagged types, in a compact binary form that a tiny decoder can parse without a schema. A short integer takes one byte and keys can be integers instead of strings, which is how a message that is verbose in JSON can shrink to a fraction of its size.

The IETF built it with constrained devices in mind: CoAP uses it as a standard content format, COSE provides signatures and encryption over it, and it underlies SUIT firmware manifests. The trade-off versus Protocol Buffers is that CBOR does not require a shared schema, which simplifies evolution but means field names or numbering conventions must still be agreed. See CoAP explained.

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