Useful Spot
Useful Spot is a collection of free, browser-based tools that do one job each and do it without an account, an upload, or a watermark. Everything runs client-side, so the data you paste never leaves your machine.
Chart makers
Paste a column of numbers, get a publication-ready chart, download it as a PNG. The set covers the charts that show up in stats homework and business decks:
- Bar graph maker labels and values, vertical or horizontal, sortable.
- Box plot maker box-and-whisker plots with quartiles, outliers, and multiple groups side by side.
- Histogram maker pick the bin width or bin count, see the distribution.
- Line graph maker one or more series over an x-axis.
- Scatter plot maker paired x/y data, optional trend line.
- Dot plot maker the stacked-dot chart from intro statistics.
- Pie chart maker categories and values, percentages worked out for you.
Text tools
- Word counter, character counter (with and without spaces), and sentence counter -- live counts as you type, for essays, tweets, and meta descriptions.
- Compare two lists paste two lists and get what's in both, what's only in the first, and what's only in the second. Handy for reconciling exports.
How it's built
Django renders every page to static HTML at build time, so the site is just files behind nginx. Each tool is a registry entry: drop in a tool.py and a template and the URL, homepage card, and sitemap entry appear on their own. The charts use Plotly; the tool scripts are tested under Node against a small DOM shim rather than a headless browser. It shares a framework with my other tool sites — Calculator Convert, Calculator Formula, and Randomize Choice.