One record per line
Each line can be parsed independently, so a single malformed record can be found without losing every valid row.
Free · Local · No upload
JSONL Viewer & Validator
Paste or open JSON Lines, pinpoint invalid rows, search records, preview fields as a table, and export valid data as JSON or CSV.
Line 1 ✓ {"id":1}
Line 2 ✓ {"id":2}
Line 3 ✕ invalid JSON
Line 2 ✓ {"id":2}
Line 3 ✕ invalid JSON
Files never leave your browser.
View and validate JSON Lines
Use a local file or paste text. Empty lines are ignored; every other line is validated independently.
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Validation results
0valid rows
0invalid rows
0detected columns
0input bytes
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| Analyze JSONL to preview valid records. |
Invalid lines
- No validation errors yet.
When JSONL is better than a JSON array
Useful for logs and exports
JSONL is common in event logs, model training data and large exports because records can be appended or streamed.
Private browser processing
This viewer reads local files in your browser. It does not upload the dataset or require an account.
Continue working with JSON
JSONL viewer questions
What is JSONL?
JSONL, JSON Lines and NDJSON describe the same basic format: one complete JSON value per line.
What happens to invalid rows?
They are excluded from preview and exports, but listed with their original line number and parse error.
How large can a file be?
The viewer accepts up to 5 MB and 20,000 non-empty lines to keep browser interaction responsive.