Open and query Parquet, CSV and XLSX files locally with SQL

Inspect, filter and query Parquet, CSV, JSON and Excel files directly in your browser with DuckDB. No upload, no setup, 100% local.

Blazing Fast

Your data never leaves your machine. All processing happens locally without any server communication.

Query Parquet, CSV, TSV, TXT, JSON, JSONL and XLSX files with automatic schema inference and type detection.

1
Open a file
Drag and drop a Parquet, CSV, JSON or XLSX file onto the drop zone above, or click Browse to select it from your computer.
2
Schema detected instantly
Queryfiles.app reads the file locally and automatically infers column names, data types and an initial SQL query.
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.

What file formats does Queryfiles.app support?: Queryfiles.app supports Parquet, CSV, TSV, TXT (including .gz compressed variants), JSON, JSONL, NDJSON and XLSX files. The format is detected automatically from the file extension.
Is my data sent to any server?: No. All file reading and SQL processing happens locally in your browser using DuckDB WebAssembly. Your data never leaves your device.
Do I need to install anything?: No. Queryfiles.app runs entirely in your browser. Open the page, drop a file and start querying. No download, no account, no signup required.
What SQL dialect does Queryfiles.app use?: Queryfiles.app uses DuckDB SQL, which is closely compatible with PostgreSQL syntax. It supports SELECT, WHERE, GROUP BY, HAVING, ORDER BY, CTEs (WITH clauses), window functions and rich built-in functions.
Can Queryfiles.app handle large files?: Queryfiles.app handles files of several hundred megabytes on most modern devices. Performance depends on available browser memory. Very large files (multiple gigabytes) may be slower.

Documentation

// DISCOVER TIPS, TUTORIALS, AND COMPARISONS FOR LOCAL DATA ANALYSIS IN THE BROWSER.