Input & Output: The "Input" textarea is where you type, paste or upload your text. The swapped result is shown in the "Output" textarea, ready to copy or download.
Group size (default: 2): The number of adjacent letters packed together and reversed. With 2, pairs swap: "hello" becomes "ehllo". With 3, packs of three reverse: "flower" becomes "olfrew".
Swap incomplete groups (off by default): When a word's length is not a multiple of the group size, the leftover letters at the end form a short group. Off leaves them as-is - "flower" with size 4 gives "wolfer"; on swaps the leftover too, giving "wolfre".
Preserve case (on by default): The case follows the original position. In "Cows are white" the first letter stays capital, so the result is "Ocsw rea hwtie". Off lets each letter keep its own case and move with it: "oCsw rea hwtie".
Hyphens - Stop / Swap / Skip: "ice-cream" with size 2 becomes "cie-rcaem" (Stop, each part swapped), "ci-ercaem" (Swap, the hyphen moves with the letters), or "cic-eerma" (Skip, the hyphen is ignored then put back).
Apostrophes - Stop / Swap / Skip: The same three rules apply to apostrophes. "you're" with Stop gives "uoy'er"; Swap treats the apostrophe as a letter; Skip ignores it and reinserts it.
Load an example: Loads a sample sentence into the "Input" field and resets the options to their defaults so you can test the tool instantly.
Upload a file: Reads a text file from your device into the "Input" field - handy for swapping saved text.
Copy & Download: "Copy" puts the output on your clipboard for pasting elsewhere; "Download" saves it as a text file.
Swap Letters button: The central action - it reverses the letter groups in every word using your chosen options and writes the result to the "Output" field.
Clear & Reset: Clears both textareas and resets the tool to its initial state.