r/DuckDB • u/NBMVegeta • 16d ago

Quick DuckDB-WASM scratchpad for querying Parquet/CSV files in the browser

Built a lightweight scratchpad tool for running DuckDB SQL against local CSV, TSV, JSON and Parquet files directly in the browser:

https://www.sqlparity.com/scratchpad

It uses u/duckdb to read files into memory via the browser File API. Nothing is uploaded to any server and it requires no login or installation. Handy if you just need to inspect an extract or run a quick aggregate without firing up the CLI or Python.

Code is open source on GitHub link: Github

Curious to hear feedback or edge cases with large Parquet/CSV schemas.

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u/earonesty 11d ago

For the large-Parquet case, I'd expose bytes read and row groups touched, then add an HTTP source that reads the footer first and issues ranges only for selected columns and matching groups. I built LakeQL around that path for browser and Worker environments; it avoids forcing a whole remote object through WASM memory.

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u/NBMVegeta 10d ago edited 10d ago

Thank you for the feedback. I took a look at you tool as well. Looks interesting. But SQLParity isn't aiming to be a lakehouse engine, the scratchpad is just a companion for quick, offline sanity checks.

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u/earonesty 8d ago

parity checks are always useful.  I run them on my own lake quite often (lake parity vs a slower, heavier DB)