SumizAI vs fullmoon

What fullmoon is

What fullmoon is

fullmoon is a free, open-source app for chatting with private, local language models, like DeepSeek R1, optimized for Apple silicon. It runs fully offline, and the developer states it collects no user data at all — the entire conversation stays on the device.

Key features

The app supports models like Llama-3.2-1B-Instruct-4bit and Llama-3.2-3B-Instruct-4bit, enabling smooth on-device performance without needing an internet connection. It runs across the whole Apple platform family — iOS, iPadOS, macOS, and visionOS — giving a consistent experience regardless of which device the user is on. Theme, fonts, and the system prompt can all be customized freely in the app's settings.

Who it's for

fullmoon appeals to Apple device owners who want a private, fully offline AI assistant without sending a single byte of data to the cloud. visionOS users get one of the few chat apps actually optimized for that platform.

Use cases

In practice, fullmoon works well for private conversations with no internet connectivity, such as on a flight, testing smaller local models optimized for an Apple phone or tablet, and as an entry point into local AI for someone who has never run a model on their own hardware before.

Pricing and business model

The app is entirely free and open source — no subscriptions, accounts, or hidden fees. The only cost is the Apple hardware needed to run your chosen model.

Limitations and what to watch for

The models available in fullmoon are relatively small (1B–3B parameters in the base configuration), so answer quality lags behind larger cloud models on more complex tasks. The app runs exclusively on Apple devices, ruling out Windows or Android users.

AI notes with no network connection

fullmoon offers no lasting notes system of any kind — it's a pure chat interface running offline. Anyone wanting to keep an answer as a ai notes entry has to copy it out by hand into a separate notes app once the conversation is over.

Offline as a core feature, not a fallback mode

Unlike many apps that offer offline mode as an add-on for when there's no network, fullmoon is designed from the ground up as a tool that fully works without the internet — that's not an exception, it's the default way it operates. That philosophy matters especially for a ai notes entry saved after a conversation somewhere with no signal, where the only alternative would be waiting for a connection.

Smaller models as a deliberate tradeoff

The decision to mainly support smaller models, like the 1B or 3B parameter variants, instead of trying to squeeze large models onto a phone, comes from a realistic assessment of mobile hardware — the developer prioritizes smooth performance and reasonable response times over maximum quality at the cost of lag.

What's worth checking before choosing

Before installing, check whether your Apple device has enough power to smoothly run your chosen model size, especially on older phones or tablets.

Bottom line

fullmoon is a simple, fully private AI assistant for Apple devices, at the cost of the limited power of smaller local models and no support for other platforms. Anyone who wants ai notes from such conversations to land automatically in a searchable archive needs a separate notes app.

Comparison with SumizAI

fullmoon and SumizAI differ in scope. fullmoon is a simple chat interface with a local model, with no lasting notes system. SumizAI is a notebook built around the conversation with an AI model — including a local Ollama, one of seven supported providers, for a similar level of privacy — where answers worth keeping land automatically as Markdown files in a vault on the user's own disk. Anyone who wants a simple, fully offline chat on an Apple device will pick fullmoon; anyone who wants these notes from such conversations to build a lasting archive will find SumizAI the better-fitting tool.

What SumizAI is

A note-taking application built around a conversation with an AI model. You ask a question, the answer streams back, and the answers worth keeping become Markdown notes — filed into a vault that is a folder on your own disk.

A vault is a directory holding base.md, a generated table of contents up to six levels deep, and a notes/ folder with one .md file per note. Before a note is written it is checked against the ones already there, so the fourth note about the same idea gets merged instead of added. Links between notes are ordinary Markdown links to files that exist.

The model is never ours: you bring your own API key to one of seven providers — Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server — and pay that provider directly. A question sends the table of contents plus at most five relevant notes within a 24,000-character budget, and the app shows you which five it used.

Every answer kept this way becomes one of these ai notes, ready to search again months later without hunting back through old chats.

Side by side

Where they differ

• fullmoon is a place to have the conversation. SumizAI is not a chatbot — the conversation is the input, not the product. What comes out of it is a .md file with a title, a place in base.md and a duplicate check against the notes already in the vault. If you only want to talk to a model, you do not need SumizAI.
• AlternativeTo's description of fullmoon does not mention an AI model. That is the whole starting point in SumizAI: you have a conversation with a model on your own API key, and the answers worth keeping become notes without you filing them.
• fullmoon is open source (MIT), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for fullmoon. The guarantee SumizAI offers instead is structural rather than legal: the notes are Markdown files in a folder you chose, so they open in any editor whether or not the application is running.
• AlternativeTo's description of fullmoon does not mention Markdown, so check what format your notes end up in before you fill it up. SumizAI writes standard .md files to a folder you picked, and an unpaid account can still export all of them.

Which one to pick