OpenUtau aims to solve problems with fewer steps. It is not designed to replicate UTAU features exactly.
Extensible real-time phonetic editing.
Includes phonemizers for different phonetic systems (VCV, CVVC, Arpasing, etc.) in many different languages (English, Japanese, Chinese, Korean, Russian and more).
Expressions replace the standard UTAU "flags" for tuning.
The built-in WORLDLINE-R resampler supports curve tuning, similar to many vocal synth editors.
Internationalisation, including UI translation and file system encoding support.
Unlike UTAU, there is no need to change your system locale to use OpenUtau.
Smooth preview/rendering experience.
Pre-rendering allows OpenUtau to render vocals before playback, saving time during editing and tuning.
Supports ENUNU AI singers. See the for more info.
Easy-to-use plugin system.
Versatile resampling engine interface.
Compatible with most UTAU resamplers.
Runs on Windows (32/64 bit), macOS, and Linux.
What it doesn't do
While OpenUtau can do very minimal mixing, it will not replace your digital audio workstation of choice.
OpenUtau does not aim for Vocaloid compatibility, except for some limited features.