SumizAI vs Zettlr

What Zettlr is

AlternativeTo files Zettlr under Note-taking, Text Editor. It is recorded as Free, Open Source — GPL-3.0, from Germany, EU. It ships on Mac, Windows, Linux, Flathub, PortableApps.com. The topics its entry raises are linked notes, LaTeX, code and web search.

That is our reading of the record. For AlternativeTo's own wording, see its page for Zettlr — 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's description of Zettlr 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.
• Zettlr is open source (GPL-3.0), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for Zettlr. 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 Zettlr 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.
• Zettlr is described in terms of linking notes together. SumizAI links them too, but deliberately without a syntax of its own: a link is an ordinary Markdown link, [Title](file-name.md), and the model may only point at a file that actually exists. There are no wiki-style [[…]] links to lose on export.
• AlternativeTo lists no mobile version of Zettlr. SumizAI runs on macOS, Windows, iOS and Android.
• Zettlr's description mentions searching the web. SumizAI does not browse: the material a question can draw on is your own vault — the table of contents plus at most five notes — and whatever the model already knows.
• Both are run from the EU: SumizAI's operator is registered in Poland and the servers are in Germany.

Which one to pick