SumizAI vs Canto Notebook

What Canto Notebook is

Canto is a private AI notebook for Mac powered entirely by local artificial intelligence — all model inference happens on the device via native Metal GPU acceleration, so no note ever leaves the user's computer. It's one of the few notepad apps offering a full AI feature set with zero cloud dependency.

The app ships with 11 built-in local models supporting tool calling, running via Metal GPU acceleration — this requires Apple Silicon (M1 or later) and a minimum of 8 GB RAM, enough for the default Granite 4.1 3B model (2.1 GB) or Qwen 3.5 4B (2.9 GB), with the option to pick larger, more accurate models on stronger hardware.

AI embeddings let it understand the meaning of content, not just word matching — Canto can instantly surface relevant information from thousands of notes, including code examples from saved notebooks, building semantic connections between seemingly unrelated entries in the user's ai notes archive.

After the first model download (a one-time operation requiring an internet connection), Canto runs completely offline, offering unlimited AI assistance, semantic Memory Links, and semantic search with no further query costs — a one-time fee for the premium version unlocks that unlimited AI use permanently.

Data security rests on a local AES-256-encrypted SQLite database — notes, code, and Memory Links embeddings are stored locally in encrypted form, and with iCloud Drive Sync enabled, Canto writes encrypted sync data to the user's own iCloud Drive folder, using a Sync Passphrase the user chooses themselves.

The key security claim — Canto never uploads readable ai notes content to any server owned by the app's creators — means even the Canto company itself has no technical way to read a user's notes, a rare, strong privacy guarantee compared to most competing cloud-based notepads.

A serious limitation is exclusivity to Apple Silicon — older Intel-based Macs can't support the Metal GPU acceleration required for local model inference, excluding a significant share of the existing Mac user base from full ai notes content backed by local artificial intelligence.

For lawyers, doctors, and other professionals bound by confidentiality who want to use AI features while taking notes with no risk of client data leaking to an external cloud provider, Canto offers a rare combination of advanced AI capabilities with an absolute guarantee of data locality.

For developers keeping a notebook of code fragments and explanations of technical solutions, understanding code through embeddings means Canto can find a similar problem solved months earlier based on a verbal description, not just an exact match on a function or variable name — a real advantage over plain text search in a large notes archive.

It's also worth adding that a one-time-fee (rather than subscription) model for unlimited AI is rare in the local-AI notepad category — most competitors bill model usage on a subscription basis even for local processing, while Canto offers a one-time entry cost with no further charges for each additional piece of ai notes content processed by the model.

In short, Canto is a solid, fully local AI notebook for Mac with Metal GPU acceleration and a one-time fee for unlimited use — an excellent option for Apple Silicon users prioritizing privacy over the cross-platform sync convenience typical of cloud-based these notes systems.

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

• Both mention AI. The difference is whose key it runs on: SumizAI never resells inference — you connect one of seven providers (Anthropic, OpenAI, Gemini, Groq, OpenRouter, a local Ollama or your own server) with your own API key and pay that provider directly. Check what Canto Notebook does with the model bill before comparing prices.
• Canto Notebook is freemium: there is a free tier and a paid one, and the line between them is the thing to read before committing. SumizAI has one plan at a dollar a month, so there is no feature held back for a higher tier — and an unpaid account still opens and exports every vault it already has.
• AlternativeTo's description of Canto Notebook 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.
• AlternativeTo lists no mobile version of Canto Notebook. SumizAI runs on macOS, Windows, iOS and Android.

Which one to pick