Free online data tools

Open spreadsheet files such as XLSX, XLS and CSV in the browser and convert them to other formats.

Run a real Postgres compiled to WebAssembly in the browser and try SQL against it.

Demo UI of sql.js, SQLite compiled to JavaScript, for running queries on in-memory databases.

Try the Papa Parse CSV parser on pasted or uploaded text and see the parsed rows and config effects.

Converts between many code and data formats, such as JSON to TypeScript, SVG to JSX and CSS to JS.

JupyterLab running entirely in the browser with a WebAssembly Python kernel, no server needed.

Edit, simplify and convert geographic data such as Shapefile, GeoJSON and TopoJSON in the browser.

Format SQL for many dialects with configurable indentation and keyword case.

DuckDB SQL shell that runs entirely in the browser via WebAssembly, reading local and remote files.

Configurable random test data generator exporting to SQL, CSV, JSON, XML and more.

Runs the R language entirely in the browser using WebAssembly.

SQLite playground for debugging and sharing SQL snippets, with the option to load your own data.

Drop in an SQLite file to look at tables and run SQL in the page.

Web environment for reading and analysing texts, with frequencies, trends and visualizations.

Datasette running in the browser through WebAssembly to explore SQLite and CSV files.

Review pane for calibrating an LLM judge: load a promptfoo CSV, mark your own labels and see where they differ from the judge.

Opens CSV, TSV or log files for searching and filtering by column.

Reads a CSV in the page and reports each column's type, gaps, spread and outliers, then drafts a data dictionary to copy.

Infers a Google BigQuery table schema from sample JSON.

Generates MySQL table definitions from a JSON sample.

Swaps the delimiter in a CSV file, for example from commas to semicolons.

Rearranges CSV data so rows become columns.

Scans a CSV file for rows with missing or empty fields and lists them.

Inserts new columns into a CSV file at a position you choose.