Duck-UI

What it does

Duck-UI is a browser-based SQL editor that runs DuckDB entirely in WebAssembly. Users load CSV, JSON, or Parquet files from their local disk or a URL, write SQL queries, and see results instantly—all without uploading data to a server. The application executes queries client-side in the browser.

Who it is for

The tool targets people who need to query structured data files quickly without infrastructure setup. This includes data analysts testing queries, developers prototyping SQL logic, students learning SQL, and anyone exploring CSV or Parquet files who finds existing workflows cumbersome. The appeal is speed: no Jupyter notebook to launch, no CLI environment to configure, no hosted service account to set up.

Pricing

The site does not show prices.

How it stands out

Duck-UI eliminates backend infrastructure by running entirely in the browser. Users avoid data upload friction and keep files local on their machine. The browser-based approach also sidesteps latency from server round trips. Because DuckDB's WebAssembly runtime handles computation, the editor remains responsive for typical analytical queries on moderately sized datasets.

What a founder should check

Incumbent workflows and switching costs. The main competitors are Jupyter notebooks, CLI tools like the DuckDB CLI itself, and hosted analytics platforms like Observable or Metabase. Founders should assess how much friction really exists in those workflows for the target user. Jupyter notebooks are already free and integrated into many analysts' development environments. The CLI is installed locally. Switching to a new tool requires habit change, and the switching cost is low only if Duck-UI offers meaningfully faster iteration.

Performance limits and data size moat. WebAssembly SQL execution works well for small-to-medium datasets, but performance constraints exist. Founders should test real query complexity and file sizes that users actually encounter. If a competitor builds a native desktop application or optimizes further, or if users routinely exceed browser memory limits, the WASM advantage fades.

Distribution and discoverability. The product is free and browser-native, which removes pricing friction but creates a different challenge: how do data analysts and engineers discover it? Most analysts already have working query tools. Growth depends on word-of-mouth, developer communities, and organic search. Founders should verify whether there is enough demand for an ultra-lightweight query tool to sustain a business or community around it.