100% local — no upload, no setup

Run DuckDB SQL queries in your browser – no installation

The full DuckDB analytical engine runs inside your browser via WebAssembly. Query any file format with standard SQL.

DuckDB is now available directly in your browser. Queryfiles.app embeds DuckDB via WebAssembly so you can run analytical SQL queries on Parquet, CSV, JSON and XLSX files without installing anything.

Everything you need, nothing you don't

Full DuckDB in the browser

The complete DuckDB analytical SQL engine runs inside your browser via WebAssembly. No server, no cloud, no installation.

All major file formats

Query Parquet, CSV, TSV, JSON, JSONL and XLSX files from a single SQL interface with automatic type detection.

Private by design

All data stays on your device. DuckDB processes everything locally without any network communication.

How it works

  1. 1

    Open a file

    Drag and drop a Parquet, CSV, JSON or XLSX file onto the home page, or click Browse to select it from your computer.

  2. 2

    Schema detected instantly

    Queryfiles.app reads the file locally and automatically infers column names, data types and an initial SQL query.

  3. 3

    Query with SQL

    Edit the SQL in the built-in editor powered by DuckDB, run queries and explore your data in real time, all inside your browser.

Frequently asked questions

What is DuckDB?
DuckDB is an open-source in-process analytical database optimised for fast SQL queries over columnar data. It is often described as the SQLite for analytics.
How does DuckDB run in the browser?
DuckDB compiles to WebAssembly (WASM), which allows it to run natively inside modern browsers without any server or native binary.
What SQL features does DuckDB support?
DuckDB supports most of PostgreSQL's SQL dialect including SELECT, JOIN, GROUP BY, HAVING, ORDER BY, CTEs (WITH clauses), window functions, UNNEST and a large set of built-in functions.
Is DuckDB in the browser slower than native DuckDB?
The WebAssembly version is somewhat slower than the native binary for CPU-intensive workloads, but still fast enough to query files of hundreds of megabytes in seconds for typical analytical queries.
Can I use this for production data pipelines?
Queryfiles.app is designed for ad-hoc data inspection and exploration. For production pipelines, use the native DuckDB CLI, the DuckDB server edition or integrate the DuckDB library into your application.

Ready to explore your data?

Drop a file and start querying in seconds. No account, no upload, no setup.

Related tools