I made an on-device AI TTS extension using the WebGPU implementation of Kokoro TTS, the highest-rated open source TTS according to TTS arena. It runs model inference fully in your browser, so no server costs and it's secure.

It was pretty easy to get the TTS working since the hard part (inference in javascript/webAssembly/webGPU) was done for me. I added some quality of life features on top: click to jump to a different paragraph, alt j & k for down and up, speed control, and voices (though the default voice has the highest quality).

I made the extension mainly because I noticed how good AI TTS was getting, yet every easy way to run TTS in the browser always used the old robotic non-AI voices that are hard to listen to for more than a few minutes.

Extension is open source: https://github.com/SambhavG/tts-extension. Unfortunately it's not on Firefox as I had issues with getting WebGPU and kokoro.js on Firefox to cooperate.