OpenAI made its official ChatGPT app available on the US App Store, providing voice-based input, GPT-4 support for paying users, and faster response times. The company said they will soon start the roll out to additional countries and that an Android version is in the making.

According to OpenAI, the launch of their iOS app responds to the aim of making their technology more readily accessible to users. As a side-effect, OpenAI will likely get to establish some order in the App Store, which has been flooded by many ChatGPT clients in the last few months, with several of them allegedly having 7-figure revenues. Although this does not necessarily mean all of those apps are profitable, as Twitter user Andrey Zagoruyko remarks, it clearly hints at the huge interest that ChatGPT has met among the general public.

While several comments on Hacker News point out that the app does not seem much more than a Web view wrapper around OpenAI website, it still provides a couple of distinctive features that bring an improved user experience, including full chat history and chat synchronization across devices, as well as voice input. That leads to think that the app is in fact API-based, rather than a WebView wrapper.

Voice-based input leverages OpenAI Whisper, a 1.6 billion parameter AI model that can transcribe and translate speech audio from 97 different languages. Whisper is open source and available on GitHub, including both source code and pre-trained model files. While Whisper can be used through an API, it appears that OpenAI ChatGPT app is integrating it natively for improved responsiveness.

This is confirmed by a "tear-down" analysis carried through at Emerge Tools, provider of a number of analysis tool for mobile apps. The analysis showed that the app binary takes up 41MB, of which almost the half are debugging symbols, attesting the still "experimental" nature of the implementation. The app includes a number of dependencies, such as MixPanel for analytics, DataDog for logging, Sentry for performance monitoring, and others.

As to chat history, OpenAI has provided the ability of disabling it in its last update, with the main benefit of keeping chats private to devices. When chat history is enabled, indeed, OpenAI will use it to improve their models. If you disable chat history, though, your chats will only be stored for 30 days.

As mentioned, the app is currently available only to US-based iOS users, but it will reach other countries in the next weeks, says OpenAI, while the Android version is coming soon.