All searchcode server really needs is any Linux/Windows/BSD system the Java 8+ runtime envrionment and enough disk space to store your code and the resulting index. It scales from tiny Atom powered servers to beefy Xeon systems. All builds and tests run on a system with the following runtime.
java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode)