Smile Data Format

"Smile" is a binary data format that defines a binary equivalent of standard JSON data format.

Format was specified in 2010 by Jackson JSON processor development team. First compliant implementation was included as a Jackson backend for Jackson version 1.6, released in September 2010.

Specification

Design documentation includes:

• Smile Format Specification describes format itself; how it works and what a compliant parser/generator implementations needs to do.
• Smile Format Design Goals explains rationale for design decisions concerning specification.

Community

• Smile format Google group

Documentation

• SmileFAQ
• Smile Wikipedia entry
• User documentation:
  • Understanding Smile data format

Implementations

Smile Codecs

• Java
  • Jackson provides Smile support through jackson-dataformat-smile modules) format codec
    • Full support: including streaming access, data binding and tree model (100% parity with textual JSON)
    • NEW (2017) Jackson 2.9 added "non-blocking" ((aka "asynchronous") decoding for JSON and Smile format backends
  • Protostuff project supports Smile both as a low-level data format, and as format used for its RPC implementation
• JVM, other:
  • Clojure
    • Cheshire library offers support via Jackson jackson-dataformat-smile
• C
  • libsmile is a small C-library for reading and writing Smile data.
• Go
  • go-smile Smile decoder written in Golang.
• Javascript
  • smile-js Smile decoder written in Javascript
• Python
  • PySmile Python codec

Frameworks, Systems that use Smile codec (encoder and decoder)

• Elastic Search uses Smile as transport format supports access using Smile encoding.
• Apache Solr can use Smile as the response format with the wt=smile parameter.