# Keyboard Heatmap Visualizer

> Paste any text: see which keys and fingers do the work on QWERTY, Dvorak, Colemak & co. Paste text and see a key-frequency heatmap on a QWERTY, QWERTZ, AZERTY, Dvorak or Colemak keyboard, plus finger and hand load, row usage, same-finger bigrams and hand alternation — and a table comparing how the same text would feel on each layout.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://keyboardheatmapvisualizer.usefulweb.site/ (interactive tool at https://keyboardheatmapvisualizer.usefulweb.site/tool)
- JSON API: POST https://keyboardheatmapvisualizer.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://keyboardheatmapvisualizer.usefulweb.site/api/v1/tool)
- OpenAPI: https://keyboardheatmapvisualizer.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://keyboardheatmapvisualizer.usefulweb.site/mcp - tool `keyboard_heatmap_visualizer`

## Inputs
- text (textarea, required): Text
- layout (select): Layout for the heatmap
- compare (multiselect): Compare with

## Method
- Every character is looked up on the layout (unshifted, Shift or AltGr level). Characters not on the layout are decomposed when possible (é → e) and counted as approximated; the rest (e.g. emoji) are counted as unmapped and skipped. Line breaks and tabs are skipped.
- Fingers follow standard touch typing on a row-staggered keyboard: left pinky for 1/Q/A/Z (and the ISO key left of Z), ring for 2/W/S/X, middle for 3/E/D/C, index for 4–5/R–T/F–G/V–B; mirrored on the right, with the right pinky also covering the keys beyond P/;//. The space bar counts for the thumbs.
- Same-finger bigram = two consecutive characters typed with the same finger on different keys (a key repeated, like “ll”, is not counted). Hand alternation = share of consecutive characters typed by different hands. Both exclude spaces, and a space resets the sequence.
- Home-row share is calculated without spaces. Shift and AltGr presses are counted as extra key presses but not attributed to a finger.
- The heatmap colour uses the square root of the count so that rarer keys stay visible.

## Limits
- A simplified model of typing effort: real comfort also depends on rolls, lateral stretches, keyboard geometry and habits.