Rename hundreds of files in one go, and see every new name first.
A browser cannot rename files on your disk. The ZIP holds renamed copies. Or run a script from the folder that holds your files to rename them in place; it never overwrites a file.
Drop them in. You see their current names at once.
Find and replace, change case, add numbers, a prefix or suffix, or a new extension.
Download renamed copies as a ZIP, or a script that renames the real files in place.
No. Everything happens in your browser.
A web page is not allowed to rename files on your disk. So you get either a ZIP of renamed copies, or a small script (.bat for Windows, .sh for Mac and Linux) that you run in the folder to rename the originals.
It only renames the files listed, never deletes or overwrites anything, and moves each file to a temporary name first so swapped names cannot clash. Read it in a text editor before you run it.
It adds a counter in the order shown. Set the start number, the step, how many digits to pad, and where it goes. Sort the list by name, date or size first to choose the order.
With numbering for duplicates on, the second becomes “name (2)”. With it off, the clash is marked and downloads are blocked until you fix it.
File names cannot contain \ / : * ? " < > |. These are replaced with an underscore.