Ion is a data serialization language developed by Amazon. It may be represented by either a human-readable text form or a compact binary form. The text form is a superset of JSON; thus, any valid JSON document is also a valid Ion document.
Data types
As a superset of JSON, Ion includes the following data types
- : An empty value (for JSON compatibility)
- : Boolean values
- : Unicode text literals
- : Ordered heterogeneous collection of Ion values (extension of JSON array)
- : Unordered collection of key/value pairs (extension of JSON object)
The nebulous JSON 'number' type is strictly defined in Ion to be one of
- : Signed integers of arbitrary size
- : 64-bit IEEE binary-encoded floating point numbers
- : Decimal-encoded real numbers of arbitrary precision
Ion adds these types:
- : Date/time/time zone moments of arbitrary precision
- : Unicode symbolic atoms (aka identifiers), stored as interned strings in binary format
- : Binary data of user-defined encoding
- : Text data of user-defined encoding
- : Nested list of values (equivalent to an S-expression) with application-defined semantics
Each Ion type supports a null variant, indicating a lack of value while maintaining a strict type (e.g., , ).
The Ion format permits attaching one or more annotations (i.e. a list of symbols) to any value. Such annotations may be used as metadata for otherwise opaque data (such as a blob).
Implementations
Examples
Sample document
Features seen in JavaScript and JSON5:
Features unique to Ion:
Uses
- Amazon's Quantum Ledger Database (QLDB) stores data in Ion documents.
- PartiQL, an open source SQL-based query language also by Amazon, is built upon Ion. PartiQL supported queries are used by QLDB, S3Select.
Tooling and extensions
References
External links