The .j namespace contains functions for converting between JSON and q dictionaries.


The .j namespace is reserved for use by Kx, as are all single-letter namespaces.

Consider all undocumented functions in the namespace as its private API – and do not use them.

.j.j – serialize

Syntax: .j.j x

Where x is a K object, returns a string representing it in JSON.

.j.k – deserialize

Syntax: .j.k x

Where x is a string containing JSON, returns a K object.

q).j.k 0N!.j.j `a`b!(0 1;("hello";"world"))        / dictionary
a| 0       1      
b| "hello" "world"
q).j.k 0N!.j.j ([]a:1 2;b:`Greetings`Earthlings)   / table
a b           
1 "Greetings" 
2 "Earthlings"

Type conversions

Note from the above examples that serialization and deserialization to and from JSON may not preserve q datatype.