Transport mode

Auto

With Automatic mode, Speedify decides which of the transport protocols below to use based on connection performance and other factors to try to give the best experience. This is the default and recommended mode.

UDP

UDP provides the best performance on slow and unreliable connections and is recommended for latency-sensitive applications like gaming, and live streaming. With the UDP transport, Speedify is able to use recover lost packets and keep performance higher than TCP on poor networks with high latency or packet loss.

TCP

Transmission Control Protocol (TCP) is a connection-oriented reliable protocol, which means that it guarantees in order delivery of data packets. If the data packet is lost across the network, TCP will resend the lost packets, but at the cost of lower performance. 
TCP is capable of higher maximum speed on fast and reliable networks when compared to UDP, but if your connections already suffer from high latency or packet loss, TCP maybe provide slower performance. In those cases, Multi TCP or UDP might be better choices.

Multi TCP

Uses multiple parallel TCP sockets for better performance than a single TCP socket. Recommended for very fast networks and networks with high latency or packet loss. Using multiple sockets allows some sockets to continue sending data if some are stuck waiting to resend lost packets.

HTTPS

Hypertext Transfer Protocol Secure (HTTPS) usually operates on port 443 and is the common protocol used on the Internet. This protocol can be useful on restrictive networks that block or throttle traffic on other ports, but allow web browsing. Because of the extra overhead, the HTTPS transport is typically slower than the other options above, so it is used as a last resort if other protocols are unable to connect.