Free, Private & Local-First

Private JSON SQL Playground: Fast Local Queries via DuckDB-Wasm

Execute SQL SELECT statements on JSON files. Query nested data privately in your browser with high performance.

Overview

This private JSON SQL playground allows you to run fast local queries directly in your browser. Using the built-in DuckDB-Wasm engine, you can filter, sort, and aggregate large JSON datasets without installing a database or uploading your files to the cloud. It's a secure, browser-based SQL console designed for big data analysis.

How It Works

Step 1

Load your JSON dataset into our private, no-install SQL playground.

Step 2

Write SQL queries to filter, sort, and group your data instantly.

Step 3

Run fast local queries with our secure DuckDB-Wasm engine.

Step 4

Analyze the data in your browser and then export the results for free.

Frequently Asked Questions

Is it safe to process sensitive JSON files online?

Yes. Your JSON data is processed entirely within your browser. No data is ever sent to a cloud server, making it impossible for your information to be stored, sold, or leaked. It's as secure as opening a file in a local desktop application.

Can I run SQL SELECT statements on my files?

Yes. This is a full SQL playground, not just a simple filter. You can write and execute complex SELECT statements on your local files using DuckDB SQL syntax.

Can this tool flatten nested JSON data?

Yes. The engine is designed to flatten complex, nested JSON structures into clean, tabular formats. This allows you to view and convert API responses or document-based data into spreadsheet-ready layouts without writing custom code.

What technology powers this tool?

This local-first tool is powered by DuckDB-Wasm, a high-performance engine that runs natively in the browser via WebAssembly. This allows for complex SQL queries and data transformations at speeds comparable to native desktop software.

Will processing large files slow down my other browser tabs?

No. We use Web Workers to run the data engine in a background thread. This ensures the main browser interface remains responsive and prevents the processing of large JSON files from lagging your other open tabs.

Is this tool compliant with strict corporate security policies?

Yes. This tool is ideal for environments with strict data sovereignty requirements. Since no data leaves your machine, using this browser-based utility is functionally equivalent to using a local text editor or spreadsheet application, bypassing the risks of third-party cloud uploads.

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Privacy Note: This tool is safe for sensitive data because your files never leave your computer.