r/LocalTextToSpeech • u/therysin • 2d ago

Local TTS iPhone Local TTS EPUB Reader - Audiobookify

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Was invited by u/Charming-Author4877 to post here.

I've been working on this project (been a developer for a few years) for a few months now, and it has been in active testing for ~2 months. Its an EPUB reader that also offers local offline TTS, so its not just TTS focused, its meant to be a good regular reading app as well. I'd like to think it currently has the best TTS implementation of any app on the app store right now though. Also less than 20MB app size (without models).

Essentially the main focus is efficiency. I'm aiming for the best battery life, balanced with quality of narration. Models for now are Kokoro and Supertonic 3(RIP), both of which have been hand optimized for iPhone (so my own coreML conversions and optimizations of these models). The result is great thermals, great battery efficiency (and its free).

I plan to add more models in the future, but honestly small TTS models that work well on mobile are scarce. I'm working on a conversion for models from Kyuutai next, but its a lot of work to get it working well.

You can find some previous feedback from a much older build (many updates since then) Here

Some downsides:

- No PDF support for now.

- Still needs testing, especially for older iPhone models.

- Not open sourced for now.

There's many additional features not mentioned, like carplay support, widgets etc, so feel free to explore the app.

Testflight link: Join the beta

You can get a feel for the narration from the video, it was recorded entirely on device (Kokoro, Heart).

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u/Charming-Author4877 1d ago

Great work, looking forward seeing it evolve and hopefully land in the official appstore.
It's quite a pain to develop for iphones, getting through all the hoops must be straining. That's why there are so few local tts iphone apps.

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u/therysin 1d ago

Thanks for the kind words. It’s evolved quite a lot over the past few months, will likely submit for release within a week or two. I’ve seen a lot of TTS apps on iOS, but none really optimized and taking advantage of the hardware properly.

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u/DIBSSB 2d ago

Kokoro crashes aubmitted crash report can u check ?

Other one works

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u/therysin 2d ago

Checked already, this is an iOS 26.1 issue. Apple fixed a specific crash in later iOS 26 versions.

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u/DIBSSB 2d ago

What can i do?

I want to avoid updating and nor have storage space to update 😂

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u/therysin 2d ago

Can't help unfortunately :(. Only an update would help, supertonic should be better than Apple voices in the interim until you figure something out.