What Lumen AI is
AlternativeTo files Lumen AI under Note-taking, Task Management. It is recorded as Free, Proprietary. It ships on Mac. The topics its entry raises are Markdown, linked notes and tasks.
That is our reading of the record. For AlternativeTo's own wording, see its page for Lumen AI — the facts above were read on 2026-08-16.
| Price | Free |
|---|---|
| Licence | Proprietary |
| Category | Note-taking, Task Management |
| Origin | AlternativeTo does not say |
| Platforms | Mac |
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 | Lumen AI |
|---|---|---|
| Price | $1/month, one plan, 7-day trial without a card | Free |
| Licence | Proprietary | Proprietary |
| Platforms | macOS, Windows, iOS, Android | Mac |
| Category | Note-taking — AI chat into Markdown | Note-taking, Task Management |
| Where notes live | Standard .md files in a folder you choose | Its description mentions Markdown |
| AI model | Seven providers, always on your own API key | Its description mentions AI |
| Origin | Poland, EU | AlternativeTo does not say |
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 Lumen AI does with the model bill before comparing prices.
- Lumen AI is free and SumizAI costs a dollar a month after a seven-day trial that takes no card. A dollar is what it costs to run accounts and licences without reselling the model; if free is the requirement, Lumen AI wins that row outright.
- 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 anotes/folder with one.mdfile per note. - Lumen AI 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. - Lumen AI also does tasks. SumizAI does not — no boards, no due dates, no projects. It files knowledge, not work.
- AlternativeTo lists no mobile version of Lumen AI. SumizAI runs on macOS, Windows, iOS and Android.
Which one to pick
Reasons to pick Lumen AI
- it costs nothing
- you want tasks and notes in one place
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 Lumen AI: AlternativeTo, read 2026-08-16. SumizAI is not affiliated with Lumen AI, and the name is used only to identify the product being compared.
Taken from the AlternativeTo lists: Obsidian.