isVpn(ip)

This repo holds a daily-updated VPN/datacenter/bot IP list for a binary, simple, isVpn check. I use this extensively in my own projects, so (luckily for you) I have a strong incentive to keep this list up to date. I recommend testing it against your own data/traffic, and comparing it to paid services to see if it's accurate enough for your use case.

It's based on these data sources:

• https://github.com/X4BNet/lists_vpn - VPN and datacenter IPs
• https://github.com/stamparm/ipsum - list of suspected malicious/bot IPs (I'm using >= 3 flags as threshold)
• Daily-updated private data from my own analytics (double-checked against paid API)

These all go into vpn-or-datacenter-ipv4-ranges.txt, and I will never change the location/format of that file.

Caveats:

• There are some commercial companies which provide VPNs for e.g. schools, universities, and companies. An example of this that I've found is "iboss". Just be aware that you may be detecting that a user is using a VPN, when they're actually just using their school/company/etc. internet. So if you show them a message like "Please disable your VPN to submit a vote", then they will probably be confused because they aren't personally using a VPN app / browser extension.
• Do not rely on this data if you need highly-accurate detection. Expect false negatives. But there should ideally be very few false positives - i.e. if isVpn returns true, then you can be confident(-ish) that it is indeed a VPN. If it returns false, then you should not be confident in that assessment - VPNs will sometimes slip through the cracks. You should fall back to a premium paid API when high accuracy is needed. If you need more accurate data, use a paid service like ip-api.com (I am not affiliated at all, I just like that their paid plan is cheap and unlimited, though I haven't tested their accuracy against other services).
• If you're looking for more than just a binary is/isn't, or want to know specifically whether it's a VPN vs bot vs datacenter, then this is not the repo for you. Please do not submit feature requests unless it's about a new, good data source. I'm keeping this repo very simple.

Example usage:

You can just use the lists in this repo directly, but if you're looking for an efficient JavaScript isVpn, then you can use this:

import { isVpn } from "https://cdn.jsdelivr.net/gh/josephrocca/[email protected]/mod.js";
// let { isVpn } = await import("https://cdn.jsdelivr.net/gh/josephrocca/[email protected]/mod.js");

let ip = "123.123.123.123";
if(isVpn(ip)) {
  // do something (but remember, it could be an inaccurate classification)
}

Again, I will never change the location/format of vpn-or-datacenter-ipv4-ranges.txt, so you're welcome to use that file as part of an equivalent isVpn function for other languages.

Note that mod.js fetches the updated IP list from this repo automatically once during init, and then every 12 hours via a setInterval. If you don't want that, just copy mod.js into your project and make whatever edits you want - it's just a single file.

Performance

As you can see in mod.js, an interval tree is used to get decent performance, given that the IP range list is quite large. On my laptop, queries take about 0.2ms. If you expect many queries from the same IP, you should cache the result in a Map, which can increase performance by up to ~10x. Maybe something like:

let isVpnCache = new Map();
function isVpnCached(ip) {
  if(isVpnCache.has(ip)) return isVpnCache.get(ip);
  let result = isVpn(ip);
  isVpnCache.set(ip, result);
  if(isVpnCache.size > 1_000_000) isVpnCache = new Map();
  return result;
}

Do Not Needlessly Block VPN Users

There are many valid reasons for people to use VPNs. Please do not use this to carelessly block VPN users when not required. In my case, for example, I use it to allow accepting anonymous votes as part of a ranking algorithm, which is better than forcing all users to sign up. If I were to allow anonymous votes from VPNs, then voting manipulation would be much easier. Please try to keep the web usable for VPN users.