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Castmates Review: Offline AI Character Chat for iPhone

·8 min readBy Hans Kuepper · Founder of PromptQuorum · Discovery engine for open-weight & open-source AI

Castmates (version 1.1.7 as of 19 October 2026) is a free iPhone app that, per its listing, runs a character-chat AI on the phone after a one-time model download of about 1.9 GB, with 32 ready-made characters and no account. Its in-app Pro plan removes the daily message cap and unlocks an optional adults-only Mature mode. The app is closed source; the developer names the model as Impish Llama 3B (Llama 3 based, quantized to Q4_K_M) running through llama.cpp, so the on-device claim still rests on the developer's word.

Key Takeaways

  • Developer: a single App Store seller, with no company named on the website and no public source code.
  • Maintenance: the version history shows 11 releases between 6 July and 19 October 2026, so no stale-project warning applies.
  • Reach: the App Store shows a 4.2 average from 5 ratings, so the app has little public track record.
  • Platforms: iPhone and iPad on iOS or iPadOS 17.0 or later, in English only.
  • Age: the listing rates it 18+ and the Mature mode sits behind Pro and a date-of-birth check.

📍 In One Sentence

Castmates is a closed-source iPhone app for roleplay with AI characters that says its model runs on the phone, with no account and a capped free tier.

💬 In Plain Terms

You install it, download a model once, and then chat with ready-made or self-made characters; the developer says the conversations are generated and stored on the phone.

📌Note: This review is based on the App Store listing, the developer's website and its privacy and content pages, checked on 19 October 2026. PromptQuorum has not installed, tested or benchmarked the app.

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Founder-reviewed. Castmates: AI Characters's founder reviewed this entry's technical specs and description for accuracy. The review itself remains independent PromptQuorum editorial content.

Castmates: AI Characters is an iPhone app for roleplay and character chat, listed on the App Store under the seller name Josip Markovic and, according to its privacy policy, developed and operated from Croatia. It was first released on 6 July 2026. This review reflects its App Store listing, website and privacy policy as checked on 19 October 2026.

Castmates Review: Offline AI Character Chat for iPhone

What Is Castmates?

Castmates is a roleplay app where you chat with fictional characters, each with a backstory, an opening line and three scenarios. The website lists 32 hand-written characters across eight genres (Companions, Romance, Fantasy, Sci-Fi, Anime, Historical, Mystery & Horror and Adventure), 96 scenarios in all, and says characters reply with actions and scene-setting rather than one-liners. You can also create a character with a name, tagline, persona, greeting, appearance, tone, tags and an opening scenario, and pick a style such as Friendship, Romance, Mentorship, Rivalry or Adventure.

The App Store subtitle is "Private, offline story chat", and the app takes its name from its cast of characters, the "castmates".

Get It

Castmates is installed from the App Store; no Android build, desktop build or source code is offered. The links below are the ones the listing and the developer's site use.

Platform
Where to get it
iPhone and iPadApp Store (iOS or iPadOS 17.0 or later, 35.6 MB)
Websiteget-castmates.com
Privacy policyget-castmates.com/privacy (updated 10 October 2026)
Content and safetyget-castmates.com/age-suitability
Termsget-castmates.com/terms

Version reviewed: 1.1.7, released on 19 October 2026 per the App Store listing. The developer says the app needs an iPhone with 6 GB of RAM or more; phones with 4 GB or less get an explanation instead of the model download, so check your iPhone before you install. The model is Impish Llama 3B (Llama 3 based, Q4_K_M, about 1.9 GB), run through llama.cpp with a 4,096-token context.

Pricing

Castmates is free to download, and Pro is sold as a monthly or annual subscription or as a one-time lifetime purchase. The prices below are from the US App Store as of 19 October 2026 and differ by storefront. Subscriptions renew until you cancel in the App Store.

Plan
What it includes
US price
Free30 messages a day, 1 custom character$0
Pro monthlyUnlimited messages and characters, Mature mode$6.99/month
Pro annualSame as monthly$29.99/year
Pro lifetimeSame as monthly, bought once$44.99

The German, Spanish and French stores show €7.99, €34.99 and €49.99; the Japanese store ¥1,100, ¥5,000 and ¥7,000; the Brazilian store R$ 49,90, R$ 199,90 and R$ 299,90. The free tier includes the whole standard cast and needs no account.

How to Get Started

Setup follows the order described on the website and listing; PromptQuorum has not run these steps.

  1. 1
    Install the app
    Why it matters: Download Castmates from the App Store; the website says no sign-up, email or profile is needed.
  2. 2
    Download the model on Wi-Fi
    Why it matters: The first run fetches a one-time model file of about 1.9 GB, which you can delete later to free space. After that, the developer says the app works without a connection.
  3. 3
    Pick or create a character
    Why it matters: Choose one of the ready-made characters and a scenario, or build your own; the free tier allows one custom character.
  4. 4
    Optionally unlock Pro
    Why it matters: Pro removes the daily limit and is required for the Mature mode, which uses the same model and needs no extra download.

Features Confirmed by the Sources

Every item below comes from the App Store listing, the website or the privacy policy.

  • Session memory. The app summarizes past sessions so characters can recall you; the privacy policy says memories are stored on the phone and can be cleared by deleting a conversation's memory.
  • Returning to a chat. The 1.1.7 release notes add a "Previously" recap and tappable suggestion chips after a character's first reply.
  • Custom avatars. A custom character can take its avatar from your photo library.
  • Model control. Settings include on-device model management, a content-lock PIN and the Mature-mode switch.
  • Battery use. The FAQ says replies draw power much like a game and that nothing runs in the background.

Privacy and Network Use

The developer says conversations, custom characters, avatars and memories stay on the iPhone and that the company never receives, sees or stores them. The policy names one remote download: the one-time model file, hosted on Cloudflare R2.

The App Store label reads "Data Not Linked to You", in line with the privacy policy, last updated on 10 October 2026, which says anonymous usage events go to Mixpanel (app opens, onboarding progress, paywall views and message counts, tied to a random on-device identifier, with IP-based location disabled) and that RevenueCat tracks subscription status through an anonymized app-user ID. The policy says these events hold no message content and nothing that identifies you, and it does not state how long Mixpanel keeps them. Purchases go through Apple.

📌Note: The app is closed source, so none of these claims can be checked in code, and PromptQuorum has not audited network traffic. Anyone handling confidential data should verify the behavior on their own device.

Age Rating and Content Controls

The App Store rates Castmates 18+ and flags frequent sexual content or nudity and suggestive themes; the developer's content page calls it safe-for-work by default. The details below come from that page, and PromptQuorum has not tested how well the controls hold up.

  • Default mode. Romance and mature themes appear, but an on-device guard fades intimate scenes to black; the page says "Castmates is not a pornography app".
  • Mature mode. Optional and for adults: it needs an active Pro plan, a one-time date-of-birth check (entries under 18 are refused), the PIN if one is set, and enough device memory for the mature model.
  • Content-lock PIN. A parent or guardian can set a PIN in Settings; it is stored only as a salted hash.
  • Always blocked. An on-device filter on chat messages and created characters blocks any sexualization of minors and other clearly illegal content in every mode.
  • Reporting. Every AI message and character has a Report action.
  • Fiction only. Characters are fictional and not a source of medical, legal or psychological advice, including coach or mentor personas.

Who Should Use It

  • Adults who want character roleplay without creating an account. The free tier covers the standard cast.
  • People who prefer chats kept on the phone. The developer says nothing is uploaded, with the caveats in the privacy section.
  • Hobby writers who want their own characters. Custom characters have their own persona, tone and opening scenario fields.

What We Could Not Verify

  • Hands-on quality. PromptQuorum did not run the app, so reply quality, speed, battery use and the real strength of the content filter are not assessed.
  • Source code and license. The app is closed source and no public repository was found.
  • Traffic. PromptQuorum has not audited network traffic, so the analytics described in the policy are not independently verified.
  • Company details. The website shows only "© 2026 Castmates" and a hidden support email; the privacy policy gives no legal entity.
  • Track record. The app is about three months old and the sources give no support commitment.

Competitors and Alternatives

SillyTavern

Platforms:
Windows, macOS, Linux, web
Price / license:
Free / AGPL 3.0
Key difference:
Open-source roleplay front end that connects to model backends you run
Articles about SillyTavern (9)

Also mentioned in:

+7 more not shown

MemoryAI

Platforms:
iOS, Android
Price / license:
Free / closed source
Key difference:
Offline chat with editable memory and a PIN-locked Kid Mode
Articles about MemoryAI (1)

Competitor details change often; confirm each app's current price, license and platforms on its own listing.

Compare in directory

Frequently Asked Questions

Does Castmates have voice chat?

Neither the website nor the App Store description mentions voice features; Castmates is described as a text chat with actions and scene-setting.

Does it work without an internet connection?

Per the developer, yes once the model is installed. The model download, purchases and the anonymous usage statistics described in the privacy policy involve the network.

Can I use it on an iPad or an Android phone?

The listing allows iPhone and iPad on version 17.0 or later; none of the sources mention an Android version.

Is my chat used to train a model?

The privacy policy says the company never receives, sees or stores conversations, and it contrasts this with cloud AI apps that log chats. PromptQuorum has not verified this.

Can I delete the model?

Yes, the website says the model file can be deleted to free space; it is downloaded again when you want to chat.

From the Maker

Josip Markovic, the developer behind Castmates, shared the following about the app and the reasons for building it. It is presented as the developer's own words, lightly edited for readability, not as PromptQuorum's independent editorial assessment:

"I built Castmates because every character app I tried wanted an account and sent every message to a server. A 3B model on a phone sounded too small for real stories, so most of the work went into making it hold a scene: session summaries so characters remember you, guards that catch the model breaking character, and a lot of eval runs on a Mac before anything ships. Next up is a faster first download and seasonal characters, starting with three Halloween ones."

— Josip Markovic, developer

Verdict

Castmates is a free iPhone roleplay app that says its character chat runs on the device, with 32 ready-made characters, custom characters, session memory and age controls for its optional Mature mode. It is also actively updated, with a release on the day this review was checked. Against that, it is closed source, about three months old, rated by few users, English only, and it needs an iPhone with 6 GB of RAM or more. It suits adults who want account-free character chat and accept a young, closed app; readers who want open code and their own models can compare SillyTavern or PocketPal AI.

Sources

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