JSONL / JSON Lines Validator

Validate JSONL (JSON Lines) files online. Each line is validated as a separate JSON object. Used with AI/ML datasets, logs and streaming APIs. Browser-based.

Your data never leaves your browser

JSON Validator

Check if your JSON is valid with detailed error messages

JSON Formatter & Beautifier

Format and validate JSON with syntax highlighting online

JSON Schema Generator

Generate JSON Schema from JSON data

Frequently Asked Questions

What is JSONL format?

JSONL (JSON Lines) stores one JSON object per line. Used for streaming, log files, AI training datasets (OpenAI fine-tuning uses JSONL). Each line must be valid JSON.