Skip to main content


Laurence MorganAbout 2 min


Concatenated JSON


The following description is taken from Wikipediaopen in new window:

Concatenated JSON streaming allows the sender to simply write each JSON object into the stream with no delimiters. It relies on the receiver using a parser that can recognize and emit each JSON object as the terminating character is parsed. Concatenated JSON isn't a new format, it's simply a name for streaming multiple JSON objects without any delimiters.

The advantage of this format is that it can handle JSON objects that have been formatted with embedded newline characters, e.g., pretty-printed for human readability. For example, these two inputs are both valid and produce the same output:

Single line concatenated JSON


Multi-line concatenated JSON

  "some": "thing\n"
  "may": {
    "include": "nested",
    "objects": [


Because of the similiaries with jsonlines (jsonl), the examples here will focus on jsonlines examples. However concatenated JSON doesn't need a new line separator. So the examples below could all be concatenated into one long line.

Example JSON lines documents taken from jsonlines.orgopen in new window

Tabulated data

["Name", "Session", "Score", "Completed"]
["Gilbert", "2013", 24, true]
["Alexa", "2013", 29, true]
["May", "2012B", 14, false]
["Deloise", "2012A", 19, true] 

This format is equatable to generic and csv.

Nested objects

{"name": "Gilbert", "wins": [["straight", "7♣"], ["one pair", "10♥"]]}
{"name": "Alexa", "wins": [["two pair", "4♠"], ["two pair", "9♠"]]}
{"name": "May", "wins": []}
{"name": "Deloise", "wins": [["three of a kind", "5♣"]]}


Similarities with jsonl

The advantage of concatenated JSON is that it supports everything jsonlines supports but without the dependency of a new line as a separator.

Eventually it is planned that this Murex data-type will replace jsonlines and possibly even the regular JSON parser. However this concatenated JSON parser currently requires reading the entire file first before parsing whereas jsonlines can read one line at a time. Which makes jsonlines a better data- type for pipelining super large documents. For this reason (and that this parser is still in beta), it is shipped as an additional data-type.

Default Associations

  • Extension: concatenated-json
  • Extension: json-seq
  • Extension: jsonc
  • Extension: jsonconcat
  • Extension: jsons
  • Extension: jsonseq
  • MIME: application/concatenated-json
  • MIME: application/json-seq
  • MIME: application/jsonc
  • MIME: application/jsonconcat
  • MIME: application/jsonseq
  • MIME: application/x-concatenated-json
  • MIME: application/x-json-seq
  • MIME: application/x-jsonc
  • MIME: application/x-jsonconcat
  • MIME: application/x-jsonseq
  • MIME: text/concatenated-json
  • MIME: text/concatenated-json
  • MIME: text/json-seq
  • MIME: text/jsonc
  • MIME: text/jsonconcat
  • MIME: text/jsonseq
  • MIME: text/x-json-seq
  • MIME: text/x-jsonc
  • MIME: text/x-jsonconcat
  • MIME: text/x-jsonseq

Supported Hooks

  • Marshal() Supported
  • ReadArray() Works with JSON arrays. Maps are converted into arrays
  • ReadArrayWithType() Works with JSON arrays. Maps are converted into arrays. Element data type is json
  • ReadIndex() Works against all properties in JSON
  • ReadMap() Not currently supported.
  • ReadNotIndex() Works against all properties in JSON
  • Unmarshal() Supported
  • WriteArray() Supported

See Also

  • * (generic): generic (primitive)
  • [[ Element ]]: Outputs an element from a nested structure
  • cast: Alters the data type of the previous function without altering it's output
  • csv: CSV files (and other character delimited tables)
  • foreach: Iterate through an array
  • format: Reformat one data-type into another data-type
  • hcl: HashiCorp Configuration Language (HCL)
  • json: JavaScript Object Notation (JSON)
  • jsonl: JSON Lines
  • open: Open a file with a preferred handler
  • pretty: Prettifies JSON to make it human readable
  • runtime: Returns runtime information on the internal state of Murex
  • toml: Tom's Obvious, Minimal Language (TOML)
  • yaml: YAML Ain't Markup Language (YAML)
  • index: Outputs an element from an array, map or table
  • mxjson: Murex-flavoured JSON (deprecated)

Read more about type hooks

This document was generated from builtins/types/jsonconcat/jsonconcat_doc.yamlopen in new window.

Last update:
Contributors: Laurence Morgan