Chitin – gives structure
to your squishy bits

Chitin is a wire format for your data. You could transfer Chitin messages over a TCP/IP socket, or write them to a file.

Chitin is especially aimed at being able to give structure to data without needing a parse and copy pass. For example, chitin format data inside an mmapped file will be readable without extra copies.

Direct data access is made possible by embracing fixed size data. You can think of Chitin messages like the IETF protocol diagrams of old, except computer managed. This is in stark contrast to formats such as Protocol Buffers, where the message is essentially a sequence of variable-length type-length-value submessages, recursively, and most processing would copy the content out into fixed-size data structures linked with pointers.

A Chitin message can contain variable length data, but only after all the fixed fields.

Chitin manages schema versioning and protocol evolution by versioning whole messages. Chitin combines message type and version information into a single identifier for efficiency.

Chitin is language-independent, but at this time only a Go library exists. That library uses code generation to gain good performance.

Status: the spec is starting to shape up, just about everything else is missing. Be patient, or join us to help out! https://github.com/chitin-io/web

Example of a schema

THIS WILL CHANGE

chitin v1

envelope Bar {
	messages {
		1: Person v1
	}
}

message Person v1 {
	wire format: v1
	options {
		align: 4
	}

	slots {
		age uint16
		_ [2]byte
		foo uint32
	}
	fields {
		name string
		website url
		data bytes {
			align: 8
		}
	}
}