100% local — no upload, no setup

Open and query CSV files online with SQL

View, filter and query .csv, .tsv and .txt files directly in your browser. Powered by DuckDB, 100% local.

Queryfiles.app handles CSV, TSV and other delimited text files with automatic delimiter detection, full type inference and a built-in SQL editor. Drop your file and start querying in seconds.

Everything you need, nothing you don't

Auto-delimiter detection

Queryfiles.app automatically detects whether your file uses commas, semicolons, tabs or other separators.

SQL queries on CSV

Filter rows, aggregate data and run complex queries with the full DuckDB SQL dialect.

Private by design

Your CSV files stay on your device. No upload, no server, no risk of data exposure.

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 CSV formats are supported?
Queryfiles.app supports .csv, .tsv, .txt and their compressed variants (.csv.gz, .tsv.gz). Delimiters such as commas, semicolons and tabs are detected automatically.
Can Queryfiles.app handle large CSV files?
Yes. DuckDB processes CSV files efficiently in memory. Files of several hundred megabytes are well supported on most modern devices.
Can I filter and sort CSV data with SQL?
Yes. You can use SELECT, WHERE, ORDER BY, GROUP BY and other standard SQL clauses once your CSV file is open in Queryfiles.app.
Does Queryfiles.app infer column types automatically?
Yes. DuckDB samples your CSV to detect numeric, text and date columns automatically, so you can query them with the correct types right away.
Can I export the results after querying?
Yes. After running a query, you can export the result as CSV, Parquet or XLSX directly from the Queryfiles.app interface.

Ready to explore your data?

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

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