Most JSON formatters break when you paste JSONL because they expect a single JSON object or array.
JSONL isn’t broken — it’s different.
This tool is built specifically for JSON Lines (ndjson). It treats each line as an independent JSON object while providing professional formatting, editing, and validation tools.
Perfect for ML engineers, data scientists, and developers who need to safely format, modify, and convert back to clean JSONL without breaking structure.
JSONLify is the first online editor built just for GPT fine-tuning.
It validates your data against OpenAI’s format, so no more hidden errors.
Upload, edit, and export prompt-completion pairs — all in your browser.
