Can a VPN usage be detected?

[amme]

Hello everyone!

I'm currently discovering how to use VPN and how reliable it is. Are there tools that can detect I'm using a VPN?

I came across some IP location tools that show not only IP, country, region but if VPN use is true/false. Like this for example https://www.abstractapi.com/ip-geolocation-api

It returns the security part among other data:

"security": {
"is_vpn": false
},

I checked and when I use VPN it returns the masked IP data and shows "is_vpn": false, so doesn't recognize that I use VPN. However, is it possible that other geolocation services may detect VPN?

Thanks!

[psyche]

there are some sites that could detect VPN usage. However there are also top notch VPNs that has a feature to counter this.

[vicyclesix]

VPN clients can be difficult to detect as they typically use a port such as 443 over UDP or TCP which is normally open on a firewall. ... Once you select a VPN server, an encrypted connection is created between your client and the VPN server. All of your Internet bound activity is then routed through this VPN connection.