Filename extension .sml Extended from JSON | Type of format Data interchange Standard no RFC yet | |
Internet media type application/x-jackson-smile (proposed) Website wiki.fasterxml.com/SmileFormatSpec |
Smile is a computer data interchange format based on JSON. It can also be considered as a binary serialization of generic JSON data model, which means that tools that operate on JSON may be used with Smile as well, as long as proper encoder/decoder exists for tool to use. The name comes from first 2 bytes of the 4 byte header, which consist of Smiley ":)" followed by a linefeed: choice made to make it easier to recognize Smile-encoded data files using textual command-line tools.
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Efficiency
Compared to JSON, Smile is both more compact and more efficient to process (both to read and write). Part of this is due to more efficient binary encoding (similar to BSON, CBOR and UBJSON), but an additional feature is optional use of back references for property names and values. Back referencing allows replacing of property names and/or short (64 bytes or less) String values with 1- or 2-byte reference ids.
Implementations
Libraries known to support Smile include: