JSON Lines Validator
12 toolsValidate and format JSONL files.
Runs in your browser — your files and text stay on your device
Validate JSON Lines (JSONL) files, where each line is a separate JSON value. Each line is checked on its own and invalid lines are listed with the parse error, and you can copy the lines re-serialized as minified JSON. The check runs in your browser.
Format & ValidateTree ViewJSON DiffJSON → CSVJSON ↔ YAMLJSON ↔ XML→ TypeScriptSchema GeneratorSchema ValidatorJSONPath TesterSort KeysJSON Lines
2 lines — all valid
Line 1: valid
Line 2: valid
How to use this tool
- 1Paste JSON Lines (JSONL) — one JSON object per line.
- 2Each line is validated independently; any invalid lines are highlighted.
- 3Copy the minified, re-serialized output.
Frequently asked questions
What is JSONL used for?
JSON Lines is a common format for logs and streaming data — each line is a standalone JSON value, so files can be processed line-by-line without parsing the whole file at once.
Is my data uploaded anywhere?
No, validation and formatting run entirely in your browser.