What Eidos is
AlternativeTo lists Eidos without a category. It is recorded as Free, Open Source — AGPL-3.0, from China. It ships on Online, Windows, Mac, Linux. The topics its entry raises are plugins.
That is our reading of the record. For AlternativeTo's own wording, see its page for Eidos — the facts above were read on 2026-08-16.
| Price | Free |
|---|---|
| Licence | Open Source — AGPL-3.0 |
| Category | AlternativeTo does not say |
| Origin | China |
| Platforms | Online, Windows, Mac, Linux |
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
| Side by side | SumizAI | Eidos |
|---|---|---|
| Price | $1/month, one plan, 7-day trial without a card | Free |
| Licence | Proprietary | Open Source — AGPL-3.0 |
| Platforms | macOS, Windows, iOS, Android | Online, Windows, Mac, Linux |
| Category | Note-taking — AI chat into Markdown | AlternativeTo does not say |
| Where notes live | Standard .md files in a folder you choose | AlternativeTo does not say |
| AI model | Seven providers, always on your own API key | Its description does not mention AI |
| Origin | Poland, EU | China |
Where they differ
- AlternativeTo's description of Eidos 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.
- Eidos is open source (AGPL-3.0), and SumizAI is not. If reading the source is what decides it for you, that is a real argument for Eidos. 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 Eidos does not mention Markdown, so check what format your notes end up in before you fill it up. SumizAI writes standard
.mdfiles to a folder you picked, and an unpaid account can still export all of them. - Eidos is extensible through plugins. SumizAI is not, and that is a genuine trade: you cannot bend it into something else, but there is also no plugin to keep working after the next release. What it does instead is fixed and small — a chat, a filing rule and a folder of Markdown.
- AlternativeTo lists no mobile version of Eidos. SumizAI runs on macOS, Windows, iOS and Android.
Which one to pick
Reasons to pick Eidos
- the source is open and you want to read it
- it costs nothing
- you want to extend it with plugins
- you need it to run in a browser
Reasons to pick SumizAI
- the notes you want already exist inside conversations with an AI model
- you want the filing — title, chapter, duplicate check — to happen without you
- you want the result as plain
.mdfiles in a folder you picked - you would rather pay your AI provider directly than have a note app resell the model
Facts about Eidos: AlternativeTo, read 2026-08-16. SumizAI is not affiliated with Eidos, and the name is used only to identify the product being compared.
Taken from the AlternativeTo lists: Obsidian.