Type your text, and the tool flips it upside down character by character using lookalike Unicode glyphs.
The generator maps each character to a Unicode character that looks like its upside-down equivalent, then reverses the order.
Most common letters, numbers, and punctuation have upside-down equivalents. Some special characters may not flip.
To read correctly when upside down, the text must also be reversed (mirrored horizontally) so it appears natural when flipped.