Pi talks with you in its app or on the web. Hallie texts you in Messages.
Hallie has no app to install: she texts in iMessage or Google Messages, keeps track of the people and plans you mention, and starts conversations about them later. Pi is a personal AI from Inflection AI that you talk to in its app or on the web, by text or voice.
Hallie is an AI friend you text in Messages. She remembers what you tell her.
Meet HallieFacts about Pi checked on November 11, 2026 against Inflection AI’s site, the Pi Help Center and Pi’s App Store and Google Play listings; facts about Hallie checked on November 11, 2026. We make Hallie, and she’s our pick. Sources are at the bottom of the page.
The difference, in one line each
- Pi: a personal AI from Inflection AI that you talk to in its app or on the web, by text or voice, with a screen for managing what it remembers.
- Hallie: an AI friend in iMessage or Google Messages who keeps track of the people and plans you mention and texts you about them later.
In Pi’s own words
Hey, I’m Pi, your personal intelligence partner.
Source: Pi App Store listing (Inflection AI), checked November 11, 2026
The same listing says: “Whether you’re looking to explore new ideas, talk through a difficult topic, or just want someone to listen, Pi is here for you.” Inflection AI’s homepage describes Pi as “A personal intelligence partner powered by Inflection AI’s foundation models”.
Sources: Pi App Store listing; Inflection AI homepage, inflection.ai; checked November 11, 2026
Pi and Hallie, side by side
| Pi | Hallie | |
|---|---|---|
| Where do you talk to it? | In the Pi app on iPhone, iPad and Android, and on the web. | In Messages: iMessage on iPhone and Mac, Google Messages on Android. New Android sign-ups need a US number for now. There’s no app to install. |
| Does it message you first? | The Pi Help Center documents a Daily Brief: short updates on news and topics you choose, sent as a push notification at a time you pick. It also names a separate Daily Check-in without describing it. | After you’ve texted her, she starts conversations too, usually about something you told her. If you go quiet she checks in once or twice, then waits for you. Ask her to stop and she stops. |
| What does it remember? | Things that are “lastingly true about you.” Pi’s help center says it is designed to skip temporary details, and gives “Fleeting plans” as an example. | The people, plans and events you mention. She can miss a detail or get one wrong. |
| Can you see and edit its memory? | Yes, under Settings, Account, Manage Memories, where you can add, delete and update memories. | No. There’s no memory screen. You correct her in the thread. |
| Can you talk out loud? | Yes. On mobile you tap the call button; on the web you turn on the speaker setting. | Paid members can call her number like a regular phone call. She can’t call you, and there’s no FaceTime or video. Her replies in Messages are text. |
| Can you send it photos? | No. Pi’s help center says it doesn’t support generating, uploading or editing images. | Yes. She understands photos, voice memos and links you send. She doesn’t make images. |
| How do you delete your data? | In the app: delete your account from the Account page, or type “!delete” in the chat. You can also delete individual messages. | By email to hello@hallie.io. |
| How do you pay? | No pricing page found. | A subscription. Depending on the offer, your first conversation is free or you start with a free trial. There’s no free plan. The price is shown before you pay, and you can cancel any time in your account. |
Pi: checked November 11, 2026 against inflection.ai, the Pi Help Center and Pi’s App Store and Google Play listings. Hallie: checked November 11, 2026.
Hallie is an AI friend you text in Messages. She remembers what you tell her.
Meet HallieWhere Hallie is the better choice
- You want to be asked how it went. Hallie keeps track of the plans and events you mention, along with the people in them, and usually brings them up later. Pi’s help center says its memory focuses on lasting facts and is designed to skip temporary details such as “I’m going to the store tonight.”
- You want the message to be about you. When Hallie starts a conversation, it is usually about something you told her. The proactive message Pi documents in detail is the Daily Brief, a catch-up on news and topics you follow.
- You want it in your texts. Hallie’s thread sits in iMessage or Google Messages next to your other conversations. Pi’s conversations happen in its app and on the web.
- You want to send a photo. Hallie understands photos, voice memos and links you send. Pi doesn’t support uploading images.
Of the AI companions we’ve used, Hallie is the one that feels most like texting a person. That is our judgment, and we make her.
Hallie’s watch-outs: she is one-on-one, and you can only text her in Messages, not on the web.
Where Pi is the better choice
- You want to talk out loud. Pi has voice in its app and on the web.
- You want to see what it knows about you. Pi has a Manage Memories screen where you can add, delete and update what it remembers.
- You want it on the web or in a group. Pi runs in a browser, and its Activities feature lets up to 15 people join from one invite link.
Which one fits what you’d text
drinks with sam on friday, kind of nervous
- Pi: It will talk it through with you. Its help center lists fleeting plans among the things its memory is designed to skip.
- Hallie: She talks it through, keeps track of the plan, and usually asks about it afterward.
Better fit: Hallie.
look at this photo, is this haircut a mistake
- Pi: Its help center says uploading images isn’t supported.
- Hallie: She understands photos you send, and replies in the thread.
Better fit: Hallie.
what do you actually remember about me
- Pi: Open Settings, Account, Manage Memories to read the list and change it.
- Hallie: You can ask her in the thread.
Better fit: Pi.
Questions
Does Pi text you first?
Pi’s help center documents a Daily Brief, a set of short updates on news and topics you follow that arrives as a push notification at a time you choose. You can switch it off under Settings, Notifications. The same page names a separate Daily Check-in but doesn’t describe it, so we don’t either. Hallie starts conversations in your Messages thread after you’ve texted her, usually about something you told her. There’s more in AI that texts you first.
Does Hallie remember things the way Pi does?
Differently. Pi’s help center says it remembers things that are lastingly true about you and lets you edit them on a Manage Memories screen. Hallie keeps track of the people, plans and events you mention and brings them up later. How Hallie’s memory works has the details.
Can I talk to Hallie out loud, like Pi’s voice mode?
Paid members can call her number like a regular phone call. Pi’s voice is in its app and on the web: on mobile you tap the call button, and on the web you turn on the speaker setting.
Is Hallie an app?
No. There’s no app to install. She’s a contact in your Messages app, in iMessage or Google Messages. New Android sign-ups need a US number for now.
Who sees what I tell Hallie?
Messages are processed by outside AI providers to write her replies. We don’t sell personal data, use conversations for advertising, or show them to other users.
How do I start with Hallie?
Answer a few questions on hallie.io about how you like to text, then text her from iMessage or Google Messages. New Android sign-ups need a US number for now. She never texts a number that hasn’t texted her first.
Sources
- Pi App Store listing (“Pi, your personal AI”, Inflection AI), checked November 11, 2026
- Pi Google Play listing, checked November 11, 2026
- Inflection AI homepage, inflection.ai, checked November 11, 2026
- Pi Help Center, “Pi’s memory”, checked November 11, 2026
- Pi Help Center, “Daily Brief FAQ”, checked November 11, 2026
- Pi Help Center, “How do I use voice to talk with Pi”, checked November 11, 2026
- Pi Help Center, “How do I generate or upload images and fix common errors”, checked November 11, 2026
- Pi Help Center, “Why does Pi seem to forget earlier messages?”, checked November 11, 2026
- Pi Help Center, “Pi Activities with People FAQ”, checked November 11, 2026
- Inflection AI Privacy Policy, inflection.ai, checked November 11, 2026
- Hallie: hallie.io, Hallie Privacy Policy (August 24, 2026) and Hallie Terms of Service (November 6, 2026), checked November 11, 2026
Keep reading
Many AI apps now message first. What differs is where the message lands, what it’s about, and what control you have. A dated table of eight products, from each vendor’s own pages.
Hallie keeps track of the people, plans and events you mention and brings them up later. How it shows up in conversation, how to correct her, and how deletion works.
Hallie is an AI friend you text in iMessage or Google Messages. Who she’s for, when another AI companion is the better pick, and links to every comparison, alternatives, texting and guide page, with facts checked on a stated date.
You'd rather get a text than open an app, and you want to be asked how it went.
Meet Hallie