Batch File Renamer vs Flash Renamer

Batch File Renamer is a free, open-source web app for preparing new names for multiple files and previewing the results. It processes files locally in the browser, does not upload them and leaves source files unchanged. Ten operations cover find and replace, prefixes and suffixes, case changes, numbering, date and time, regular expressions, cleanup and extension changes. Presets handle numbering, date prefixes, filename cleanup, music files, episode formatting, lowercase conversion and replacing spaces. Users can save reusable operation chains in browser local storage and undo or redo changes across 50 operation states. Validation flags invalid or empty names, reserved Windows device names, trailing spaces or periods, names over 255 characters and duplicate selected outputs. Export creates a ZIP archive containing selected valid files as renamed copies rather than changing originals on disk. Modern browsers support file import; folder picking is best in Chromium-based browsers, and save-picker support varies. The MIT license permits use, modification and distribution subject to its notice. The web plan costs nothing and needs no installation or registration.

Flash Renamer has no write-up on Specifiction yet; its figures are above.