I Built a Convenient but Extremely Dangerous Website That Can Bulk Replace All Files in a Specified Folder

#webdev #chatgpt #ai #javascript

Have you ever needed to replace text across all files in a folder at once? For example:

・Updating old API keys scattered across multiple files
・Performing large-scale renaming in HTML/CSS/JS projects
・Replacing specific phrases in Markdown or text logs in bulk

Normally, tasks like these require specialized apps (like VSCode’s regex replace) or command-line tools (sed, awk, find, grep, etc.), which can be intimidating for beginners.

So I thought:

“Couldn’t this be done more simply, directly in a browser?”

That’s why I created this site.

🚀 Features of This Site

This tool recursively scans all text files in a specified folder and replaces the search string in bulk.
Best of all, it runs entirely in the browser. No installation needed. Works across platforms.

✅ Key Features

・Select folders via drag & drop
・Processes files in subdirectories as well
・Automatically skips binary files (images, audio, etc.)
・Detects garbled text and excludes suspicious files
・Optionally creates a ZIP backup before replacements

🔥 Supported Browsers

・Google Chrome
・Microsoft Edge
　　(Not supported on Safari or Firefox because they don’t support the File System Access API)

🛡 How to Use Safely

・First, try it on a test folder
・Always enable the backup (ZIP) option

👨‍💻 Technical Background

This tool leverages File System Access API and JSZip:
・File System Access API
　　・Next-gen API that enables browsers to read/write local files
　　・Works in the latest versions of Chrome and Edge
・JSZip
　　・A JavaScript library for ZIP compression and decompression
・Garbled Text Detection
　　・Filters out files by calculating the ratio of invisible characters or replacement characters (�)

Thanks to these technologies, it’s possible to perform bulk replacements with nothing but a browser—no installations required.

📥 Try It Out

If you’re interested, give it a try:
It’s super handy, but use with caution!

👉 https://uni928.github.io/ReplaceAllFileAtOneDirectory/index2

Want to check for any suspicious behavior? Download the source code here:

👉 https://github.com/uni928/ReplaceAllFileAtOneDirectory

🙏 Finally

This tool fulfills the need for “simple bulk replacement,” but misuse can instantly corrupt your files.
(If replacements go wrong and are applied to production environments, bugs may occur. Backups are highly recommended.)

Use it on production folders at your own risk.