Developer utilities
JSON Lines, line by line.
Validate NDJSON records in the browser, pinpoint malformed lines, and convert a valid stream to a formatted JSON array.
Paste JSON Lines
Validation result
Validate the input to see line-specific results.
Source and limitations
Parsing uses the browser’s built-in JSON.parse. Errors report the original 1-based line number and, when the runtime provides it, a 1-based column.
Blank lines are ignored for convenience. This is a full-text validator, not a streaming parser, and it does not enforce a particular NDJSON schema or object-only record policy.