.JSONL·File Extension

What is a .jsonl file?

A .jsonl file is a JSON Lines File — Newline-delimited JSON, one JSON object per line for streaming large datasets.

In the mime-db registry it has no registered standard MIME type. When serving this file over HTTP, use a Content-Type that matches its actual format.

When served over HTTP, responses should set the following header:

# No standard MIME type is registered for .jsonl

Common software that reads/writes .jsonl:

• Configuration files
• Data interchange between systems
• API request and response payloads
• Logs and data exports

• Open the file with jq, make your changes and save.
• Most editors preserve the original formatting and encoding — avoid changing the charset.

• Create a new file and save it with the .jsonl extension, or export this format from jq.

• mime-db
• refnet data sources

Updated 2026-08-18