JSON Lines Formatter and Converter
Validate JSON Lines or NDJSON data, normalize one-record-per-line text, and convert records to JSON arrays in your browser.
Paste JSON Lines, NDJSON, log records, or streaming data exports to validate each record and produce copy-ready output. Everything runs locally in your browser.
How to use this JSON Lines tool
JSON Lines stores one complete JSON value on each line, which makes it common for logs, analytics exports, queue payloads, and data pipelines. Paste the records, choose whether blank lines should be ignored, then validate, normalize the one-line records, or convert them into a JSON array.
The validator reports the exact line and best available column for malformed records so you can fix the source quickly. A valid line can be an object, array, string, number, boolean, or null, though object records are most common in operational data.
Use array conversion when a downstream tool expects one JSON document. Use normalized JSON Lines when you need one compact record per line. This page does not upload data, evaluate log contents, infer schemas, or repair invalid JSON automatically.
Common gotchas
- Each non-blank line must be a complete JSON value; a multi-line object is standard JSON, but it is not valid JSON Lines until it is condensed to one line.
- Trailing commas, comments, and single-quoted strings are not part of standard JSON Lines data.
- For reliable interchange, JSON Lines files are commonly encoded as UTF-8 and often use
.jsonlor.ndjsonfile names.
