Last Updated: February 18, 2026

Welcome to JSONL Viewer, a free, fast, and privacy-focused tool for viewing and inspecting JSON and JSON Lines (JSONL) files directly in your browser.

In an era of bloated software and complex installations, we believe developer tools should be fast, simple, and private. JSONL Viewer loads instantly, requires no downloads, and works entirely offline once the page is loaded.

Built with Standard Web Technologies

JSONL Viewer is engineered from the ground up using HTML5, CSS3, and Vanilla JavaScript. By avoiding heavy frameworks and build systems, we ensure the tool loads in milliseconds and remains compatible across all modern browsers and devices.

Privacy and Security

Your data never leaves your device. JSONL Viewer uses the browser's built-in FileReader API to parse files entirely on your local machine. No data is uploaded to any server, and no cookies are used to monitor your usage of the tool itself.

Thank you for choosing JSONL Viewer. We are committed to keeping this tool fast, free, and private.