Now on the App Store · iPhone

Roleplay with 35 AI characters on your iPhone.

Roleplay with 35 hand-crafted characters who narrate the scene, stay in role, and remember every story you build together. The whole cast lives on your iPhone, and your conversations never leave it.

Meet the cast

100% on-device · No account · Works offline

Castmates app on iPhone showing an in-character roleplay chat with Detective Cross, a noir detective who narrates the scene, flanked by painted portraits of the elven ranger Lyra and the vampire Countess Elise.

Why Castmates

Roleplay with depth, kept to yourself

A cinematic cast, real roleplay depth, and a model that runs entirely on your iPhone. That's the whole point — and everything else builds on it.

Stays in character

Detective Cross doesn't answer like an assistant — he lights a cigarette and narrates the room. Characters reply with actions and scene-setting, never flat one-liners.

It remembers you

Castmates summarizes past sessions, so characters recall who you are and the story keeps building. Pick up the thread days or weeks later.

On-device & private

The AI runs entirely on your iPhone. After a one-time model download, your conversations are generated and stored on-device — never sent to a server.

Works on a plane

No signal, no problem. Once the model's installed, Castmates runs fully offline — on the subway, on a flight, off the grid.

A cast of 35

Thirty-five hand-crafted characters across eight genres, each with a distinct voice, a backstory, an opening line, and a painterly portrait.

Build your own

Create custom characters end to end — persona, greeting, appearance, tone, tags, and a signature opening scene. Set the avatar from your photo library.

See it in action

The real app, screen by screen

Not mockups — actual Castmates, running on iPhone.

Castmates roleplay chat with Detective Cross narrating a noir scene on iPhone.

They stay in character

Replies come with actions and scene-setting — never flat one-liners.

Castmates Discover screen showing recommended characters and genres.

Browse the cast

35 hand-crafted characters across 8 genres, recommended for you.

Castmates character creator screen with name, tagline, and category fields.

Build your own

Persona, tone, and opening scene — with an avatar from your photo library.

Castmates scenario picker listing several roleplay scenarios to start.

Drop into a scene

127 ready-made scenarios across the cast — or write your own.

Castmates settings showing the on-device model, content lock, and subscription.

Your controls

On-device model, a content-lock PIN, and optional Mature mode — your call.

Up and running in minutes

From download to deep in a scene

  1. 1

    Download & set up

    Install from the App Store and grab the on-device model once (~2 GB). After that, you're fully self-contained — and fully offline.

  2. 2

    Pick or create

    Choose a character and drop into one of 127 built-in scenarios — or build your own character and opening scene.

  3. 3

    Roleplay

    Start the scene. Characters act, narrate, and stay in role — and they remember where you left off, every time you come back.

The cast

35 characters. 8 worlds. One you.

Trade barbs with Detective Cross. Range the wilds with Lyra. Match wits with Nova the sardonic ship AI, sail with Captain Morgan, get sworn loyalty from Hattori, or accept Countess Elise's invitation into the dark.

Each character ships with a backstory, an opening line, ready-made scenarios (127 openings in all), and original portrait art. Onboarding tunes the cast to your favorite genres, styles, and tone.

Meet the full cast — every character in detail →

Your imagination, cast

Cast a character only you know

When the lineup isn't enough, build your own. Dream up anyone — a rival swordsman, a soft-spoken confidant, a chaotic AI — and shape their name, persona, and voice, then write the exact scene you want to open on. They'll roleplay exactly the way you wrote them.

  • Define the name, tagline, genre, personality, greeting, and appearance.
  • Dial in tone and interaction style — Friendship, Romance, Mentorship, Rivalry, or Adventure — then add your own tags.
  • Set the avatar by picking a photo from your library, and write a custom opening scenario to drop straight into.

Mature mode, your call

An optional Mature (18+) mode for romance-forward roleplay — SFW by default, gated behind Pro and age confirmation, and like everything else in Castmates, it stays on your device.

Privacy isn't a setting

Be unguarded. No one's listening.

Most AI apps send every word you type to a server. Castmates doesn't — the model runs on your iPhone, so your conversations never leave it. Your stories are truly yours — not training data, not someone else's server logs.

Runs on your iPhone

Local inference does the thinking. Every reply is generated on-device, and your conversations stay in the device in your hand.

No account, no profile

No sign-up, no email, no profile — nothing to leak. Your conversations are never uploaded; the app sends only anonymous, aggregate usage stats (no message content, nothing that identifies you).

Works offline

Airplane mode on, story still going. Once the model's downloaded, you can fly, ride, and roam — no connection required, ever.

On-device, not the cloud

Typical cloud AI app

  • ✕ Every message is sent to their servers
  • ✕ Sign-up and an account required
  • ✕ Chats can be logged and used to train models
  • ✕ Needs an internet connection

Castmates

  • The AI runs on your iPhone
  • No account, ever
  • Nothing you say leaves your device
  • Works fully offline

Simple pricing

Start free. Go deeper with Pro.

Try the full cast for free, then upgrade when you're hooked. Every plan keeps your conversations on your iPhone.

Free

$0

Plenty to meet the cast and start a story. No account required.

  • 30 messages per day
  • 1 custom character
  • The full SFW cast of 35
  • 3 voice call messages per day
  • 100% on-device & offline
Most popular

Pro

Everything unlocked. Cancel anytime.

Start on the free plan · Cancel anytime

  • Unlimited messages
  • Unlimited custom characters
  • Unlimited voice calls
  • Optional Mature (18+) mode

Monthly

$6.99

/month

Annual

$29.99

/year

Save ~50%

Lifetime

$44.99

Annual — Best value · ≈ $3.33/mo billed annually

Start free, upgrade when you're ready. Cancel anytime in the App Store. Subscriptions auto-renew until canceled.

Questions

Good to know

What is Castmates, and what does the name mean?

Castmates is an iPhone app for roleplay and character chat. You get a cast of 35 AI characters, and the model runs on your phone, so there's no account and your conversations stay on your device. The name is the cast you chat with: a set of characters, each one a castmate. It's written Castmates, one word, though many people search for it as "cast mates".

Is it really private?

Yes. After a one-time model download, the AI runs entirely on your iPhone — no accounts, and your conversations never leave your device. The only thing the app sends is anonymous, aggregate usage stats (no message content, nothing that identifies you).

Does it work offline?

Completely. Once the model is downloaded, Castmates runs with no connection at all — perfect for flights, subways, and dead zones.

Is it free?

Yes — the free plan gives you 30 messages a day, one custom character, and the full SFW cast, with no account. Upgrade to Pro for unlimited messages and custom characters whenever you want more.

Will characters remember me?

Yes. Castmates summarizes past sessions, so characters remember you and the story keeps building across every conversation.

Can I make my own characters?

Absolutely. Build custom characters with their own persona, greeting, tone, interaction style, tags, and opening scenario — and set the avatar from your photo library. Free includes one; Pro is unlimited.

Can I talk to the characters out loud?

Yes. Tap the phone in a chat to call a character and talk out loud. Both the speech recognition and the voice run on your iPhone, so calls stay private and work offline too. Voices are English only and need a one-time download of about 360 MB. The free plan includes 3 call messages a day, Pro is unlimited.

Can I import character cards from SillyTavern or Chub?

Yes. Castmates imports SillyTavern, Chub, JanitorAI and RisuAI cards as PNG or JSON (V1, V2 and V3), including their lorebooks and alternate greetings. The character then runs on the model on your iPhone, with no API key. An imported card counts as a custom character, and you can export your own characters as cards too.

What's Mature mode?

An optional 18+ mode for romance-forward roleplay. It's off by default, requires Pro and age confirmation, and like everything else, stays private on your device.

How much storage does it use?

The on-device model is a one-time download of about 2 GB. It lives inside the app, and you can free up the space anytime by deleting it. Mature mode uses the same model — no extra download.

What do I need to run it?

An iPhone on iOS 17 or later. Everything runs on-device, so a recent iPhone gives the smoothest, fastest replies.

Will it drain my battery?

Generating replies uses your iPhone's chip the way a game does, so long sessions use more power than texting. Day to day it's light, and nothing runs in the background.

Reviewed elsewhere

PromptQuorum covers local LLM apps for iPhone and wrote an independent Castmates review: the model, the 6 GB RAM requirement, the privacy label, and what it couldn't verify.

Coming from another app?

Your story. Your phone. No one else.

Download Castmates, pick your first character, and start a scene that's truly yours — 35 characters, 127 scenarios, all on your iPhone.

Free to start · No account · 100% on-device

Castmates

Free · On-device · 35 characters