To work with Shifter, it is recommended to choose IPv6 individual proxies.

Choose GEO: USA

Here's my personal top proxy picks.

Mobile proxies:

I buy mobile proxies from Soax, ShopProxy, Mobile Proxy Space.

IPv4 proxies:

For IPv4 it's advisable to buy individual ones to avoid blocks. You can purchase from Proxys.io (highly recommended! Perfect for Shifter), Proxy6, Proxymania.

IPv6 proxies:

I get IPv6 proxies from Proxyline and Proxys.io.

Residential proxies:

Residential can be purchased from Shifter, Proxys and Proxy Sale.

Additionally, I recommend using promo codes, which can be found here. If you still have questions about which proxies are suitable, feel free to write, and I'll answer if possible.