AI assistant for iPhone: Which AI assistant to choose on iPhone
Siri, ChatGPT, Gemini and Nia look alike in a demo and part ways in daily use. This is what each one does on your iPhone, without taking away what any of them does well.
Nia is an AI voice assistant for iPhone that turns what you say into real actions: events in your Calendar, reminders, alarms, images in Photos or lights in Home. It runs on Google's Gemini models and speaks 19 languages. Here it is, row by row, against Siri, ChatGPT and Gemini.
Compared in October 2026, with iOS 27 and that month's ChatGPT and Gemini apps.
An AI chat knows a lot and can touch almost nothing on your iPhone. Siri can touch almost everything, and with Siri AI it understands much more, for now in six languages and outside the EU. Nia understands a long sentence in your language and turns it into actions on the iPhone's apps, with the same permissions Apple gives any app.
Nia's side is not a demo integration: it is 59 actions, each with its permission, its result card and, where possible, its undo button.
Siri AI is available in beta in English, French, Japanese, Korean, Portuguese and Spanish. It requires iOS 27 and an iPhone that supports Apple Intelligence. It is not available on iPhone in the European Union. Availability checked on November 4, 2026.
What each one does on an iPhone
What matters when choosing, one sentence per cell. No built-in winner: each one wins at something.
| You want… | Nia | Siri | ChatGPT | Gemini |
|---|---|---|---|---|
| Call it by voice with the iPhone locked | No: one tap on its control in Control Centre, on the Lock Screen or on the Action button | Yes, with "Hey Siri" or the side button | No: one tap on its Lock Screen widget or on the Action button | No: one tap on its Lock Screen widget, in Control Centre or on the Action button |
| An event in the iPhone Calendar, with an alert and a place | Yes, in the iPhone's default calendar, in one sentence | Yes | No: the app does not write to Calendar | In Google Calendar, not the iPhone's |
| Reminders and alarms | Yes, in Reminders; system alarms from iOS 26 | Yes | Scheduled tasks inside ChatGPT | In Google Tasks and Keep; no iPhone alarms |
| Send a message or a WhatsApp | It leaves it written and open, and you press send | Yes, it sends once you confirm | No | Not on iPhone |
| Several actions in one sentence | Yes, in one turn and as one command | With Siri AI, yes; with classic Siri, no | Not on the iPhone's apps | Across Google apps |
| Remember what you tell it | Yes, on Plus (30 days) and Pro, on a screen where you search it, add to it or delete it | Siri AI searches your messages, emails, notes and more | Yes, with memories you can see and delete | Yes, it learns from your chats, and you can turn it off |
| Create images | Yes, and they save themselves to Photos | With Image Playground, on iPhones with Apple Intelligence | Yes | Yes |
| Languages | 19, with native voices | Many; Siri AI, for now in six languages | Dozens | Over 40 in Gemini Live |
| Work offline | "Hey Nia" and, depending on the language, dictation; understanding a request, no | The basics: alarms, timers, opening apps | No | No |
| What happens to your data | Not used to train models, neither Nia's nor Google's | Apple keeps transcripts for up to two years, tied to a random identifier and not to your account | May be used to improve its models unless you turn it off | A sample is read by reviewers unless you turn activity off |
| Price | Free, 5 commands a day; Plus $19.99 and Pro $39.99 a month | Included with the iPhone; Siri AI with a daily limit | Free with limits; paid: Go, Plus and Pro | Free with limits; paid: Google AI Plus, Pro and Ultra |
| Where it works | iPhone with iOS 18 or later, in the EU too | Every iPhone; Siri AI on iPhone 15 Pro or later and outside the EU | iPhone, Android, web, Mac and Windows | iPhone, Android, web and Mac |
"Siri" is the one in iOS 27; "ChatGPT" and "Gemini" are their iPhone apps. For Nia, the cell says what is Plus or Pro. All four change their plans and limits often: ChatGPT's and Gemini's are on their official pages, linked at the end.
Which one suits you
The honest answer depends on what you want to happen when you stop talking.
Siri
If what you use most is voice with the iPhone locked and sending messages without touching anything. With an iPhone 15 Pro or later and outside the EU, Siri AI adds personal context, in beta.
ChatGPT
If your thing is talking, writing, studying or thinking out loud, and you also use it on a Mac, on Windows or on Android. As a chat, it is among the most complete.
Gemini
If you live in Google: Gmail, Google Calendar, Keep and Tasks. Gemini Live is a great talker, and Gemini is on Android, on iPhone, on the web and on the Mac.
Nia
If you want a sentence to end up done in the iPhone's apps: the event in place, the reminder with its alarm, the image in Photos. In 19 languages and on any iPhone with iOS 18.
One sentence, four tools, one turn
This is what separates an assistant that does things from an assistant that answers: an ordinary sentence becomes several actions without you splitting them up.
"Add dinner with Luis on Thursday at 9 at Casa Lucio, remind me an hour before and tell him I have booked"
- Creates the event with its place geocoded and its length.
- Sets the alert an hour before, inside the event itself.
- Resolves Luis in your address book, on the phone.
- Opens WhatsApp with the message written, waiting for you to press send.
And all of that counts as one command, not four.
The iPhone apps Nia really touches
With the system frameworks, on the device. No odd bridges and nothing else for you to install.
The limits belong to iOS, not to each app
No app other than Siri can listen with the iPhone locked and the app closed, or send a WhatsApp or a text in your name. That goes for ChatGPT, for Gemini and for Nia. The one crack is in Japan: since iOS 26.2, another app can take the side button there instead of Siri.
About AI assistants on the iPhone
What is the best AI assistant for iPhone?
It depends on what you want to happen when you stop talking. For talking and writing, ChatGPT. If you live in Gmail and Google Calendar, Gemini. For using voice with the iPhone locked and sending messages hands-free, Siri. And if you want a sentence to end up done in the iPhone's apps, Nia.
Can I replace Siri with ChatGPT, Gemini or Nia?
Not entirely. Siri is still the system assistant and the only one that listens with the iPhone locked. Any of the others can have the Action button, a widget or a Control Centre control. The exception is Japan: since iOS 26.2, another app can take the side button there.
Can ChatGPT or Gemini create events in the iPhone Calendar?
The ChatGPT app does not write to the iPhone Calendar: its reminders are tasks inside ChatGPT. Gemini creates events in Google Calendar, which only show on the iPhone if you have that account added in Settings. Nia writes straight into the iPhone's default calendar, with its alert and its place.
What is Siri AI and is it available in the European Union?
Siri AI is available in beta in English, French, Japanese, Korean, Portuguese and Spanish. It requires iOS 27 and an iPhone that supports Apple Intelligence. It is not available on iPhone in the European Union. Availability checked on November 4, 2026.
Does Nia use ChatGPT or Gemini?
Gemini, on the server, which is the only part of the system that talks to the model. What Nia adds is everything that happens next: understanding the request in your language and turning it into actions on the iPhone's apps. It does not use ChatGPT or any OpenAI model.
Sources
Checked on October 10, 2026. OpenAI's pages could not be opened from here: what is said about them was checked against secondary sources. Siri AI availability checked on November 4, 2026.
- Apple Newsroom: Siri AI, a profoundly more capable and personal assistant powered by the next generation of Apple Intelligence, is here (14 Sept 2026)
- Apple Support: How to get Siri AI
- Apple Support: How to get the next generation of Apple Intelligence
- 9to5Mac: iOS 27.2 expands Siri AI to these new languages (16 Sept 2026)
- Apple: Siri, Dictation & Privacy
- MacRumors: iOS 26.2 Lets iPhone Users in Japan Replace Siri With Third-Party Assistants on Side Button (17 Nov 2025)
- Apple: ChatGPT Extension & Privacy
- Tom's Guide: Forget Siri: here's how to put ChatGPT Voice on your iPhone lock screen (6 Sept 2024)
- Engadget: ChatGPT Now Has A Hub For Scheduled Tasks (17 June 2026)
- OpenAI Help Center: Data Controls FAQ
- OpenAI: ChatGPT pricing
- App Store: Google Gemini
- Tech.co: iPhone Users Get New Google Gemini Widgets
- 9to5Google: Gemini Live rolls out Google Calendar, Tasks, Keep apps access (9 Aug 2025)
- The Decoder: Google rolls out Gemini memory in Europe and wants you to bring your ChatGPT data along
- Google: Gemini Apps Privacy Hub
- Google Workspace Updates: Now available: The Gemini app for Mac (15 Apr 2026)
- Google One: Plans & Pricing to Upgrade Your Cloud Storage
ChatGPT is a trademark of OpenAI, Gemini of Google and Siri of Apple. Nia is not affiliated with any of them.
Shall we begin?
Download Nia, tell it the first thing and see what happens. The free plan asks for no card.
Free to start. Requires iOS 18. In 19 languages.
Last reviewed