What is the honest one-line difference?
Notion is a database with documents on top. Obsidian is an editor over a folder of Markdown. A chat window is a place to think. SumizAI is the step between thinking and having something written down.
That is why the overlap is smaller than it looks. None of the others produce the note for you, and SumizAI does not try to be the place you write documents or model structured data.
The practical test: if your problem is "I have things to organise", the others are strong. If your problem is "the thinking happened in a chat and evaporated", that is this one.
Notion — where does each one win?
Notion wins on structured data and on teams. Databases, views, relations, permissions, comments — none of which SumizAI has or is trying to have.
SumizAI wins on capture. In Notion a conversation with a model becomes a page when you paste it there and clean it up, which is exactly the step people stop doing in week three.
There is also a data-shape difference worth stating plainly: Notion holds your content in a service, and SumizAI holds it as .md files in a folder you chose. Both positions are defensible; they are just different.
Obsidian — is SumizAI a replacement?
No, and they are close enough that they work well together. Both are Markdown files in a folder; the difference is who writes them.
Obsidian is an outstanding editor and graph over notes you author, with a plugin ecosystem SumizAI has no ambition to match. SumizAI authors notes from conversations, files them and connects them, and produces exactly the kind of folder Obsidian is happiest opening.
A common arrangement: SumizAI as the intake, Obsidian pointed at the exported vault for reading and long-form editing. The links work in both because they are relative Markdown links between real files.
Just using ChatGPT or Claude directly — what am I missing?
Retrieval you can trust, and a durable artefact.
A chat window keeps a history you can scroll and, increasingly, a memory feature that surfaces things it decides are relevant. What it does not give you is a set of documents with titles, summaries and an index, on your disk, that outlive your account with that provider.
There is also a portability argument. SumizAI is provider-agnostic by design — seven providers, your key — so the library does not belong to whichever model you were using when you built it.
What about the AI features built into other note apps?
Most of them are an assistant bolted onto an editor: a sidebar that can summarise the page you are on or draft a paragraph into it. That is useful and it is a different shape.
SumizAI is the other way round. The conversation is the primary interface and the note is the output, which is why filing, duplicate detection and linking happen automatically — they are pipeline stages, not commands you remember to run.
The tell is what happens when you do nothing. In an editor with AI features, nothing happens. Here, a note exists.
When should I not use SumizAI?
When you need a shared workspace. There are no multi-user vaults, no comments, no permissions.
When you need your notes on two devices. There is no sync between devices today — your laptop and your phone are two separate libraries.
When you do not think out loud with a model. If your notes come from reading, meetings and your own drafting, an editor serves you better; there is no conversation for SumizAI to capture.
When you want structured data — a CRM, a tracker, a database of anything. That is Notion's job and it is good at it.
Can I use it alongside my existing system?
Yes, and that is the common case rather than a compromise.
Because a vault is a folder of Markdown with a generated index, it drops into an existing setup: point Obsidian at it, keep it in a Git repository, sync the folder with whatever you already use for folders.
The one thing worth deciding up front is direction. SumizAI writes into its folder, so treat that folder as an inbox that fills itself, and do long-form editing wherever you prefer.
What would make you choose something else?
If you want one tool for everything, this is not it — it is a small application with a narrow job.
If your work is collaborative at the note level, you need a tool built for that, and retrofitting collaboration onto local files is not something we are pretending to have solved.
If you would rather pay one vendor for both the app and the model, the bring-your-own-key model will feel like homework. It buys you a dollar-a-month price and provider independence, but it is a genuine trade.
Seven days, no card, one dollar after that
Point SumizAI at a folder, connect the AI provider you already pay for, and start a conversation. The first note files itself.