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NDJSON Linter
Report every NDJSON record’s strict JSON and framing outcome without repairing or hiding invalid records.
Strict UTF-8 NDJSON or JSONL file, Pasted LF-normalized records
Complete JSON diagnostic report
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Paste NDJSON or choose a UTF-8 file, which takes precedence and preserves framing.
- Select Lint records and download ndjson-report.json.
- Read strictValid together with JSON-valid, JSON-invalid, not-parsed and framing counts. A completed diagnostic job does not mean the source is valid.
Examples
true followed by no final LF is JSON-valid but receives a missing-final-lf issue, so the strict report marks the stream invalid.
Limitations
- 5 MiB input, 50,000 records, 1 MiB content per record, 200,000 cumulative visited values including failed parse prefixes, 40 levels, 2 KiB per diagnostic and 10 MiB complete report; 30-second processing limit.
- Blank, bare-CR and unexpected-BOM records skip JSON parsing. Missing final LF alone does not. Original parser diagnostics use UTF-16 character wording where present and explicitly mark truncation.
- Global byte/node/depth/report limits abort the whole job without a partial successful report. No repair, JSON5, multiline pretty-JSON, schema validation or recovery within one malformed record.
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