JSON Lines Validator
12 toolsValidate and format JSONL files.
Runs in your browser — your files and text stay on your device
Everything you'd need a dedicated JSON app for — formatting, a collapsible tree view, structural diffing, converting to/from CSV, YAML, and XML, generating TypeScript interfaces and JSON Schemas, querying with JSONPath, and validating JSON Lines — runs entirely client-side using your browser's native JSON engine, so nothing you paste is ever sent to a server.
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.