SumizAI vs Simplenote

What Simplenote is

AlternativeTo files Simplenote under Note-taking, Todo List Manager. It is recorded as Free, Open Source — GPL-2.0, from United States. It ships on Mac, Windows, Linux, Online, Android, iPhone, Android Tablet, iPad. The topics its entry raises are Markdown, local files, sync and collaboration.

That is our reading of the record. For AlternativeTo's own wording, see its page for Simplenote — the facts above were read on 2026-08-16.

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.

Side by side

Where they differ

• AlternativeTo flags Simplenote as no longer developed. Whatever you put into it, you will eventually have to get back out — which is an argument for keeping notes in a format that outlives the application, and the reason SumizAI writes plain .md files into a folder you already own.
• AlternativeTo's description of Simplenote 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.
• Simplenote is open source (GPL-2.0), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for Simplenote. 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.
• Both keep Markdown, which makes moving between them mostly a matter of copying files. In SumizAI a vault is a directory holding base.md — a generated table of contents — and a notes/ folder with one .md file per note.
• Simplenote is described as something more than one person uses at once. SumizAI is not: there are no shared vaults, no comments, no permissions and no sync between devices. If the work is a team's, that is a reason to pick Simplenote over SumizAI.

Which one to pick