Pretty-print JSONL and NDJSON files in a side-by-side read-only preview — no source file modifications. Each row is formatted as indented JSON with syntax highlighting, with configurable row limits and live updates as the file changes.
Installation
Launch VS Code Quick Open (Ctrl+P), paste the following command, and press enter.
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 .jsonl and .ndjson files and the application/x-ndjson / application/jsonl MIME 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:
