Under the hood, it's actually using Google's Cloud OCR API. Not sure how well it handles 草書 or 隷書, but it does a pretty remarkable job with 行書. Also does surprisingly well with super pixelated text. I can look up words in 16-bit games trying to squeeze kanji into 16x16 sprites or something, and it holds up incredibly well.
You can also swap out the OCR API it uses. Right now I support Google and ocr.space.
You can also swap out the OCR API it uses. Right now I support Google and ocr.space.