Pretty-print JSONL and NDJSON files in a side-by-side read-only preview — no source file modifications. Each row is expanded into indented JSON with full syntax highlighting, and the preview updates live as the file changes on disk.
Features
- Side-by-side read-only preview — source file is never modified
- Each row pretty-printed with 2-space indentation and JSONC syntax highlighting
- Configurable row limit — preview as many or as few rows as you need
- Custom row count prompt for one-off inspections without changing your default
- Live refresh — preview updates automatically whenever the source file changes on disk
- Works with
.jsonland.ndjsonfiles and theapplication/x-ndjson/application/jsonlMIME types - Parse errors are surfaced inline so malformed rows are easy to spot
What it does
Opening a .jsonl or .ndjson file gives you a compact, hard-to-read wall of JSON objects. JSONL PPrint opens a read-only preview panel beside your source file where each row is pretty-printed with indentation and syntax highlighting — so you can inspect the data without ever touching the original file.
How to launch
With a .jsonl or .ndjson file open in the editor, you have three options:
- Editor toolbar — click the preview icon in the top-right of the editor to open a preview using the default row limit.
- Context menu — right-click anywhere in the file and choose JSONL: Preview JSONL or JSONL: Preview JSONL (custom rows).
- Command Palette — open the palette (
Cmd+Shift+P/Ctrl+Shift+P) and run JSONL: Preview JSONL or JSONL: Preview JSONL (custom rows).
The "custom rows" variant prompts you for a row count before opening.
Configuration
| Setting | Default | Description |
|---|---|---|
jsonlPprint.defaultPreviewRows |
10 |
Number of rows shown when using the standard preview command. |
To change the default, open Settings (Cmd+, / Ctrl+,) and search for jsonlPprint, or add it directly to your settings.json:
"jsonlPprint.defaultPreviewRows": 25