Guide
NDJSON vs JSON Arrays
Choose line-delimited records for streams and arrays for one complete JSON value.
Written by DevPouch Editorial TeamSource-review record dated 2026-10-02; see the scope and method below.
Reviewed against the listed primary reference and synthetic local workflow; this is not a runtime or security certification.
Related tools
The debugging problem
NDJSON allows per-line parsing and recovery, while a JSON array has delimiters and must parse as a whole document. The formats are not interchangeable.
A practical sequence
- Check whether each nonblank line is complete JSON.
- Report malformed line numbers without discarding good records.
- Preserve order when exporting valid lines.
- Use an array when the contract requires one JSON document.
Synthetic example
NDJSON:
{"id":1}
{"id":2}
JSON array:
[{"id":1},{"id":2}]A failure to watch for
Pasting a pretty-printed JSON array into an NDJSON viewer creates several invalid lines rather than two records.
Limits and interpretation
Line-oriented parsing cannot recover a valid JSON value split across lines.
References
FAQ
What should I verify first when using this ndjson vs json arrays workflow?
Check whether each nonblank line is complete JSON.
What can this workflow not prove?
Line-oriented parsing cannot recover a valid JSON value split across lines.