VPN & Proxy Detection — JapanDetect VPN, Proxy & Bot Traffic from Japan
Maskbreak scores every visitor's network in real time — flagging VPN exit nodes, residential proxies, datacenter ASNs, and headless browsers originating from Japan. Free API. Under 40ms server-side. No CAPTCHAs.
The networks Japan traffic actually arrives from
Japan has 742 autonomous systems on the public registry. 185 of them are hosting, cloud or transit networks holding 156.3M addresses between them — the ranges a commercial VPN or datacenter proxy exits from. Residential broadband is the rest, and that is the traffic worth watching, because a residential proxy hides inside it.
| ASN | Network | IPv4 space |
|---|---|---|
| AS17676 | GIGAINFRA SoftBank Corp. | 38.3M addresses |
| AS4713 | OCN NTT Communications Corporation | 28.6M addresses |
| AS2516 | KDDI KDDI CORPORATION | 18.1M addresses |
| AS2907 | SINET-AS Research Organization of Information and Systems, National Institute of Informatics | 8.8M addresses |
| AS17506 | UCOM ARTERIA Networks Corporation | 5.4M addresses |
| AS9824 | JTCL-JP-AS JCOM Co., Ltd. | 4.7M addresses |
| AS2497 | IIJ Internet Initiative Japan Inc. | 3.9M addresses |
| AS2527 | SO-NET Sony Network Communications Inc. | 3.9M addresses |
Largest hosting-shaped networks registered in Japan, by IPv4 allocation. Registry data, refreshed daily. A datacenter ASN is not evidence of fraud on its own — it is one signal, weighed alongside device and behaviour.
Why Japan traffic needs special scrutiny
Datacenter ASN concentration
NTT and SoftBank residential ranges are the most common origin for Asia-targeted SaaS fraud.
Residential proxy resale
Consumer ISP ranges in Japan can appear in commercial or peer-to-peer residential proxy pools. A consumer ISP label is not proof of fraud; combine it with device, session, and routing signals.
VPN exit-node clustering
The same handful of hosting providers dominate VPN exit nodes in Japan. Maskbreak maintains live mappings of these ranges so a new IP from a known VPN ASN is flagged within seconds of going live.
Antidetect browser usage
Multi-accounting fraud against Japanese-targeted SaaS, fintech, and e-commerce increasingly uses Kameleo, GoLogin, or AdsPower to spoof device fingerprints. Maskbreak scores these at the device layer, not the IP layer.
What Maskbreak detects for Japan traffic
- Every major VPN provider's Japanese exit nodes (NordVPN, ExpressVPN, ProtonVPN, Mullvad, Surfshark, and 40+ more)
- Commercial or peer-to-peer residential proxy pools using consumer Japanese IPs
- Datacenter ASNs commonly used for automation (AWS, GCP, Azure, OVH, Hetzner, DigitalOcean, Vultr, Linode)
- Tor exit nodes and known anonymous relays advertising Japanese geolocations
- Headless browsers (Puppeteer, Playwright, Selenium) and antidetect tooling driving sessions from Japan
- Country-spoofing — when a session claims to be in Japan but the network telemetry says otherwise
One API call. Bearer token. Done.
// Server-side only: an sk_live_ key must never reach the browser.
const r = await fetch('https://maskbreak.com/v1/evaluate', {
method: 'POST',
headers: {
'Authorization': 'Bearer sk_live_...',
'Content-Type': 'application/json'
},
body: JSON.stringify({ token: req.body.monocle })
});
const { decision, country, network } = await r.json();
if (country === 'JP' && network.vpn) blockOrChallenge();
Stop Japanese VPN, proxy & bot fraud today
Free tier: 1,000 requests/hour. No card, no expiry. Detects VPN, residential proxy, datacenter, and bot traffic from Japan and 195 other countries.