Cibyl is a programming environment and binary translator that allows compiled C programs to execute on J2ME-capable phones. Cibyl uses GCC to compile the C programs to MIPS binaries, and these are then recompiled into Java bytecode. Cibyl programs are regular compiled Java programs, and Cibyl therefore performs relatively well.

With Cibyl, C programs can be ported to J2ME without switching language. It also allows C and Java code to be integrated in an easy and efficient way. The environment uses the GNU toolchain (GCC and binutils) and should work in all environments which provide them. Full-scale C applications, such as the Sarien AGI interpreter was ported to J2ME devices using Cibyl.