JSONL Viewer & Editor — JSON Lines / NDJSON
View, edit, search, and validate JSON Lines (JSONL/NDJSON) files online with row-by-row inspection, syntax highlighting, and match highlighting.
Free Web vs Desktop App
Web (Free)
- +JSONL Viewer & Editor — JSON Lines / NDJSON with basic functionality
- +No signup or account required
- +Works in any modern browser
- -Up to 5 MB / 50k rows on the web
- -Single tool per page, no integrations
Desktop App ($29 one-time)
- Unlimited size, streaming parser, jq-style filtering, send rows to HTTP Client, Database, or AI Terminal
- All 20 developer utilities in one ToolBox
- Plus terminal, HTTP client, database client, Docker manager
- AI agents, code editor, Git client, and 100+ more features
- macOS, Windows, Linux — one-time purchase, own forever
About JSONL Viewer & Editor — JSON Lines / NDJSON
A free online JSONL viewer and editor for working with JSON Lines (JSONL), NDJSON, and any line-delimited JSON. Paste content or drag-and-drop a .jsonl file and instantly get a beautified row-by-row viewer with syntax highlighting, per-row validation, expandable previews, inline editing, add/delete-row, and one-click export back to JSONL or download. Filter rows by keyword with live inline highlighting and a match counter that pinpoints exactly where each query appears. Built for LLM chat transcripts (Claude Code session logs, OpenAI completions, fine-tuning datasets), structured log streams, analytics events, ML training data exports, BigQuery / Snowflake / DuckDB row dumps, Loki and Vector log shipping, and any newline-delimited JSON payload. Everything runs 100% client-side in your browser — your data never leaves your machine — and the same JSONL workflow is included in the 1DevTool desktop app alongside HTTP Client, Database, and AI Terminal tools so you can pipe rows straight into requests, SQL, or LLM prompts.
Frequently Asked Questions
Is JSONL Viewer & Editor — JSON Lines / NDJSON free to use?
Yes! This online version is completely free with no signup required. Up to 5 MB / 50k rows on the web. For unlimited usage and full integration with 100+ developer tools, download the 1DevTool desktop app ($29 one-time).
Is my data safe?
Absolutely. All processing happens entirely in your browser. Your data never leaves your machine — nothing is sent to any server. The tool runs 100% client-side using JavaScript.
What do I get with the desktop app?
The desktop app includes JSONL Viewer & Editor — JSON Lines / NDJSON with no limits, plus 19 other developer utilities. Beyond the ToolBox, you get multi-agent AI terminals, HTTP client, database client (26 engines), Docker manager, Git client, code editor, browser preview, and more — all in one workspace. $29 one-time, no subscription.
Like this tool? There's a lot more.
Download 1DevTool to get JSONL Viewer & Editor — JSON Lines / NDJSON with no limits, plus 19 other utilities, AI terminals, HTTP client, database client, and 100+ features.