Review event logs
Turn newline-delimited events into readable records while preserving their original line order.
100% local · files never leave your browser
View tool
JSONL & NDJSON Viewer
View JSONL and NDJSON records in your browser with line-level parsing errors. Files stay on your device.
✓ Free to use✓ No signup✓ Runs locally
112 bytes · local only
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Processed entirely in this tab
Your input and result are not sent to JSON Hearth or stored on a server.
When to use it
What JSONL Viewer helps you do
JSONL and NDJSON store one JSON value per line. This viewer is useful for logs, event streams and datasets that are awkward to read as plain text.
Diagnose one bad record
Locate the line that fails to parse instead of treating the entire file as one JSON document.
Inspect exported datasets
Sample machine-learning, analytics and data-pipeline outputs before importing them into another system.
How it works
JSONL Viewer, without the upload.
Add your data
Paste a value, open a local file or begin with the working sample.
Run the tool
The transformation executes in your browser, not on our servers.
Review the result
Check the output, then copy or download it for your next task.
Important limitations
What to check before using the result
Review required
Every non-empty line must contain a complete valid JSON value.
Review required
Pretty-printed multi-line objects are ordinary JSON, not JSONL, and should use the JSON viewer instead.
Common questions
About JSONL Viewer
Does JSONL & NDJSON Viewer upload my data?
No. Your input is processed by code running in your browser and is not sent to an application server.
Is JSONL Viewer free to use?
Yes. The tool is free, requires no account and can be used directly in the browser.
What is the difference between JSONL and NDJSON?
They are commonly used names for the same line-delimited format: one valid JSON value on each line.
Can a JSONL line contain an array or primitive value?
Yes, provided the entire line is valid JSON. Object records are simply the most common convention.