Which Opera mobile browser uses proxy servers to compress webpages?

The Opera mobile browser that uses proxy servers to compress webpages is Opera Mini.

Opera Mini was designed to reduce the amount of data sent to mobile phones. Instead of having the handset retrieve and render every page directly, Opera’s servers fetch the content, process it, compress it, and send a smaller version back to the device.

This approach made browsing faster and cheaper on slow or expensive mobile connections, especially on early Java ME phones. The trade-off was reduced functionality: server-side processing could affect JavaScript-heavy or highly interactive websites. Opera Mobile, by contrast, was a more conventional browser that performed more of the work on the device. Opera GX and Opera Neon are separate products and do not define this classic compression-proxy model.