What SQL dialect is supported?

DuckDB SQL — a superset of standard SQL with analytical extensions including window functions, UNNEST, LIST functions, and more. See duckdb.org for the full reference.

How large a file can it handle?

DuckDB WASM handles files up to several hundred MB comfortably in modern browsers. Performance depends on available RAM and the complexity of your query.

Is my data uploaded anywhere?

No. DuckDB runs entirely in a Web Worker in your browser via WebAssembly. The WASM binary (~7MB) is downloaded once from a CDN and cached; your data files never leave your device.

Can I query multiple files?

Yes. Upload multiple files and reference them by name in SQL. For example: SELECT a.*, b.name FROM read_csv_auto('orders.csv') a JOIN read_csv_auto('customers.csv') b ON a.customer_id = b.id

What happened to Vortex file support?

Vortex (SpiralDB's columnar format) is not yet supported by DuckDB WASM. We'll add it when a stable DuckDB extension ships.

SQL File Explorer — Query CSV, Parquet & JSONL

Upload a CSV, Parquet, or JSONL file and run SQL queries on it — powered by DuckDB WASM. No server. Your data never leaves your browser.

How to use

1
Upload your data file
Drop a CSV, Parquet, or JSONL file. DuckDB loads it locally — no upload to any server.
2
Write a SQL query
Use full SQL: SELECT, WHERE, GROUP BY, JOIN multiple files, window functions, and more — powered by DuckDB.
3
Download results
Export your query results as a CSV file.

Why use this tool?

Full SQL on local files — SELECT, WHERE, GROUP BY, JOINs, window functions
Supports CSV (auto-detected), Parquet, JSONL, and JSON files
Powered by DuckDB WASM — the same engine used in production data pipelines
Your data never leaves your browser — runs entirely client-side

Frequently asked questions

What SQL dialect is supported?: DuckDB SQL — a superset of standard SQL with analytical extensions including window functions, UNNEST, LIST functions, and more. See duckdb.org for the full reference.
How large a file can it handle?: DuckDB WASM handles files up to several hundred MB comfortably in modern browsers. Performance depends on available RAM and the complexity of your query.
Is my data uploaded anywhere?: No. DuckDB runs entirely in a Web Worker in your browser via WebAssembly. The WASM binary (~7MB) is downloaded once from a CDN and cached; your data files never leave your device.
Can I query multiple files?: Yes. Upload multiple files and reference them by name in SQL. For example: SELECT a.*, b.name FROM read_csv_auto('orders.csv') a JOIN read_csv_auto('customers.csv') b ON a.customer_id = b.id
What happened to Vortex file support?: Vortex (SpiralDB's columnar format) is not yet supported by DuckDB WASM. We'll add it when a stable DuckDB extension ships.

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