Repair JSONL / NDJSON with Invalid Lines

Identify malformed JSON Lines, preserve good records and review all omitted data.

Step-by-step troubleshooting

1. 01

   Make an untouched copy

   Never repair the only NDJSON export in place.

2. 02

   Validate each record

   The JSON Lines tool checks one JSON value per nonblank line and reports faulty line numbers.

3. 03

   Inspect each failure

   Check quoting, brackets, control characters and accidental multiline records.

4. 04

   Export valid records carefully

   The optional salvage file omits malformed lines; it does not invent missing objects.

5. 05

   Reconcile record counts

   Compare the original and repaired line counts before importing to a database.

What if the file is still broken?

Structural checks can identify evidence of truncation, checksum errors or a format mismatch, but a successful check does not prove every application can decode the file. If critical data is missing, restore from backup, request a new copy or use a reputable specialist with permission to access the content.

For important or sensitive files, retain a copy of the original and document each recovery attempt. Avoid tools that promise guaranteed reconstruction of missing bytes.

For a practical recovery order that minimizes accidental damage, see our safe file recovery checklist. For format-specific limits, see supported formats and test scope.