Wake-word engine

For our project we need a Wake-Word or Hot Word Engine, which is local and always listens for the user to start all the other processes.


Since the finished product is supposed to be used by probably vulnerable individuals in charity organisations, we need to consider following criteria:

  • Local and private
  • Open source and free to use
  • Supported by a bigger community or company

Furthermore, it would be nice if it is easy to use and we could monetize the product, because we cannot limit the use to charity.


There are several possible engines which are the following:

  • Precise by Mycroft
  • Pocketsphinx
  • Porcupine
  • Raven
  • Snips
  • Snowboy

precise by mycroft

Available on Github under the Apache 2.0 license. It is maintained by Mycroft AI Inc Kansas City, who sell AI assistant hardware with their software and merchandise to support them self’s. It is possible to train custom wake words as documented here.

pocketsphinx by Carnegie Mellon University

Pocketsphinx is available on github and is meant for use on mobile and desktop devices. It is maintained by a team of Carnegie Mellon University and partially funded by the Defense Advanced Research Projects Agency and National Science Foundation and the CMU Sphinx Speech Consortium. Team one already uses it for their speech recognition.

Porcupine by Picovoice

Porcupine is open-source and available on github under the Apache 2.0 license. Training custom wake words is restricted to x86_64 CPU architecture.

Rhasspy Wake Raven

Raven is available on github under the MIT license. It is mainly based on the Snips engine and allows for custom wake words. There are two people maintaining the repository, who are also responsible for the Rhasspy Assistant. It is also used by the first team as wake word engine.


Snipes is available on github under the Apache 2.0 license. The last push was 14 months ago. It seems like it does not get any support anymore. It is the base for Raven.

Snowboy by Kitt-AI

Snowboy will be discontinued at Dec. 31st, 2020 as stated in the readme.md on github On one hand it is widely used and might get good Community support, on the other hand the developers stated “The field of artificial intelligence is moving rapidly. As much as we like our products, we still see that they are getting outdated and are becoming difficult to maintain.”


Since all the above are open-source wake word engines and seem to run locally which also ensures privacy, we should decide on the engine with the best support. Snowboy and Snips are EOL or don’t get much support. Porcupine requires a paid license for our use case. Raven and Pocketsphinx already get used by our other team, which only leaves us Precise.

What’s next?

Why we did not use Openssl.