RENAME

Manual

1. What RENAME does

   RENAME renames a batch of files at once — handy for tasks like "bulk rename files" or "rename files in bulk with a sequence number" when you have a pile of photos, audio, or video files that need a consistent naming pattern. You can combine five kinds of rules: find/replace, prefix/suffix, sequence numbers, case conversion, and date insertion.

2. Two modes

   This tool offers two modes: "Rename in place" and "Export as ZIP". Supported browsers show both tabs automatically; unsupported browsers only show the ZIP export tab.

   Mode	What it does	Supported browsers
   Rename in place	Pick a folder and rename the files inside it directly	Chromium-based browsers only (Chrome, Edge, etc.)
   Export as ZIP	Pick or drop files, then download a ZIP containing the renamed files	All browsers, including Safari and Firefox

3. How to use it

   (1) For "Rename in place", pick a folder; for "Export as ZIP", drop or select files. (2) Turn on the rules you want in the rules panel on the left and configure them. (3) Check the before → after names in the preview table. Rows with a conflict or an invalid name are flagged, and the apply button stays disabled until every issue is resolved. (4) "Rename in place" changes the files directly after a confirmation dialog. "Export as ZIP" downloads a ZIP file with the renamed files inside.

4. Rule details (fixed application order)

   Enabled rules are applied in this fixed order (it cannot be changed). The extension is always preserved — rules only apply to the part of the filename before the extension.

   Order	Rule	What it does
   1	Find/replace	Plain-text find and replace, with an optional case-sensitivity toggle (no regular expressions)
   2	Prefix/suffix	Adds a fixed string to the start and/or end of the name
   3	Sequence number	Inserts a running number at the start or end. Configurable start number, digit count (1–4, zero-padded) and separator (_ / - / none). Numbers follow the order files were selected in
   4	Case conversion	Converts the whole name to lowercase, uppercase, or leaves it unchanged
   5	Date insertion	Inserts the file's modified date (YYYYMMDD) at the start or end

5. Preview and conflict checking

   As you configure rules, the before → after names update live in the preview table. Rows are flagged when the result is empty, contains characters an OS can't use (/ \ : * ? " < > | or control characters), starts or ends with a dot or space, or collides with another file's new name — and the apply button stays disabled until every flagged issue is resolved.

6. How it works: in-browser processing and privacy

   All renaming logic runs entirely in your browser. Neither file contents nor file names are ever sent anywhere. "Rename in place" uses your browser's local folder access feature (the File System Access API) to rename files directly on your file system, so that step also never leaves your device. "Export as ZIP" similarly bundles the selected files into a ZIP inside the browser before downloading it.

7. Limitations

   Files inside subfolders are not included — only files directly inside the folder you pick are listed. There's no undo for "Rename in place"; a confirmation dialog appears before it runs, but back up your files first if you want extra safety. Sequence numbers support zero-padding up to 4 digits.

8. Use case: sequential photo numbering

   Turn a folder of photos into "trip_001.jpg", "trip_002.jpg" and so on: set the prefix to "trip_", enable the sequence rule with 3 digits and no separator.

9. Use case: dating a batch of recordings

   Insert the recording date at the start of a batch of audio files to make them easy to sort chronologically. Enable date insertion, set it to the start with a "_" separator, and you'll get names like "20260715_take1.wav".

10. FAQ

    Are my files uploaded to a server?

    No. Both the renaming logic and reading/writing the files happen entirely inside your browser.

    Can I use regular expressions?

    Not in this version. Find/replace only supports a plain-text exact match (with an optional case-sensitivity toggle).

    Can I rename files inside subfolders?

    No — only files directly inside the folder you pick are included. Subfolders are ignored.

    Can I undo "Rename in place"?

    There's no undo. A confirmation dialog appears before it runs, but it's worth copying your files first if you want a safety net.

    Why isn't "Rename in place" available in Safari or Firefox?

    It relies on the File System Access API (folder access with read-write permission), which is currently only supported by Chromium-based browsers such as Chrome and Edge. Use the "Export as ZIP" mode in other browsers.

    What happens if two files would end up with the same name?

    The preview table flags the affected rows, and the apply button stays disabled until the naming conflict is resolved — for example by enabling the sequence number rule.