Soft Proxy Checker | Niflheim - Free and Local

[DarkholdRT]

On forums, people often post lists of proxies – fresh ones, “leaked” ones, private ones, any kind. A file with 500–5000 lines, and everyone has the same question: Which of these actually work?

Before, you had to install Python, figure out the libraries, and write scripts. Or run the list through dubious online services that might save your proxies for themselves.

Now it's easier: opened the HTML file → uploaded the list → clicked "Check" → received the ready list of working cards. Everything is local, nothing is sent anywhere, proxies don’t leak.

How to use it.
Just download the Zip archive with the files, put it wherever you want, and double-click it. ProxyChecker.html — and it works. No installation is required, internet is only needed for the proxy check itself.

If the browser suddenly misbehaves (rare, but it happens), launch a simple server next to it: python -m http.server and open localhost:8000.
Step 1. Upload the proxy list.
Three options to choose from:

• Drag and drop the file. directly into the window (supports .txt, .csv, .list)
• Click “Choose file” — as usual
• Insert text in the right field, if you copied the list from the forum.

It supports all popular formats.

185.22.174.91:8080
185.22.174.91:8080:user:pass
http://185.22.174.91:8080
socks5://user:[email protected]:1080

If the list contains comments or garbage, it's not a problem; they will simply be skipped. Duplicates are also automatically filtered out, so there's no need to manually clean the list.

Step 2. Click "Check All"
The program will start checking each proxy:

• Is the IP live?
• Is the port open?
• In which country is it located?
• What is his provider (ASN)?

The verification speed is adjustable – the default is 5 threads, but you can set it higher. There’s a button for that. «Stop», if you change your mind.
The progress is immediately visible: green means working, red means dead, yellow means being checked.

Step 3. Collect the result.
Button “Export” opens a window where you select:

• What to export: all / only live / only dead
• What to include: only IP:port or full information (country, city, ASN)
• Format: .txt, .csv, .json, .xlsx (will open in Excel)

Important detail.
Browser cannot connecting to a proxy directly is a security limitation of all modern browsers. Therefore, the check works as follows:

1. GeoIP — country and provider are determined by IP address using a public API.
2. Port availability — checks if the server responds on this port.

This not 100% guaranteeit will let your traffic through, but it's a good initial filter. Dead and obviously non-working ones are filtered out immediately. For those who need a full check through the proxy itself, a server-side component will be required; that's a different level.

Questions and suggestions. — Post in the thread. If you need to add support for other formats, translate to another language, or anything else, let's discuss it.