ProxyChecker is a free, open-source desktop proxy checker, published at proxychecker.co and on GitHub under the GPL-2.0 license. After five years without a release, version 1.3 came out on October 12, 2026. It brought installers for Windows and macOS, a jar for Linux and a Docker image. It checks HTTP, SOCKS4 and SOCKS5 proxies and grades their anonymity with one judge, its own server.
That judge is the part to know about: every check through a proxy carries your own public IP address in the request, in plain http. This page sets out what ProxyChecker does, what 1.3 changed, how its judge works, and the free checker we maintain. We did not download or run ProxyChecker. Everything here comes from its code, its site, its release notes and its issue tracker.
What ProxyChecker does
You load one or more proxy lists, choose a protocol, and it checks them on many threads at once. Its defaults are 100 checks at a time and a 5-second timeout. It reports which proxies work, with their anonymity, response time and country, and exports the table as CSV. It checks one protocol per run: HTTP, SOCKS4 or SOCKS5, chosen in its settings.
GitHub counts 29,015 downloads of its release files, most of them version 1.2:
What version 1.3 changed
Version 1.3 answered old requests from its issue tracker. Users asked for a command-line version in 2020, a Docker image in 2022 and proxies with a username and password in 2022, and all three arrived. It also added SOCKS4, a stop button and faster loading of long lists.
Its site now says that "a proxy only counts as working if a valid judge response comes back through it". In March 2024 a user had reported that the old check was "throwing false positives".
How its judge works
A judge is a server that shows a checker what reached it through a proxy. ProxyChecker uses one, its own api.proxychecker.co, over plain http. First it asks the judge directly, without a proxy, to learn your public IP address. Then, for every proxy, it requests the judge through that proxy with your address in the query. The request line reads:
GET /?ip=<your public address>
The judge compares the address in the query with the one that connected, and returns a grade. Any proxy sees the address that connects to it; that comes with using one. What this design adds is your address written into every request, so the judge's operator receives it with every proxy you test. When the judge is down, nothing gets graded: in October 2022 a user reported a "Service Down" error on every start.
We asked the judge twice from our server on October 23, 2026, without any proxy. The second time, the query carried 192.0.2.1, an address reserved for documentation:
It answered "ELITE". The address in the query did not match the one that connected, so it graded a direct request as an elite proxy. The judge trusts the address the tool sends. The tool is open source, but the judge's server code is not published. Asked for it in 2020, the reply was that it "is really simple which is why I haven't posted it".
A free checker that compares on your computer
We make free proxy tools, and we sell residential proxies, so read this part with that in mind.
- Our free app checks from your own computer. It learns your public address once with a direct request. Through each proxy it sends a one-time code and never writes your address into the request. It compares what the judge saw with your address on your computer. Its judges run on our own domain, and it runs on Windows 10 and 11, macOS and Linux. Get it on our proxy checker page.
- Our online proxy checker needs no install. It tries HTTP, HTTPS, SOCKS4 and SOCKS5 on every line, up to 100,000 lines a run and 300,000 a day without an account.
To read the results, our guides on checking if a proxy works and on anonymity levels explain each column.
Where HProxy fits
The checkers are free. What we sell is residential proxies: Residential Lite costs $0.50/GB for one GB, falling to $0.18/GB at 1,000 GB+, and the balance does not expire. If a free list keeps failing your checks, a paid pool is the next step, and you can test it with the same tools.
What we could not find out
We did not install or run ProxyChecker, so its behavior comes from its code, its site, its release notes and its issues. We could not read the judge's server code, which is not published. Our check sent the judge a documentation address and no traffic through any proxy. It is two requests from one server at one moment. The download count for 1.3 is eleven days old.
Sources
- ProxyChecker's repository on GitHub (faiqsohail/ProxyChecker): its description, its release records with download counters and the 1.3 notes, RequestAPI.java and UserSettings.java, and issues #4, #5, #13, #17, #18 and #22, read October 23, 2026.
- proxychecker.co, read from our server on October 23, 2026.
- RFC 5737, "IPv4 Address Blocks Reserved for Documentation", January 2010.
- Our check of ProxyChecker's judge, two requests from our server, October 23, 2026.
- HProxy's app and checker code: how the app learns your address and grades, and the online checker's limits.
