The best AI second brain apps, by what they remember.
Every second brain is built from something: your notes, what you save, your screen, your voice, or what you tell a bot. Pick the one built from where your memory actually leaks. Thirteen products in six groups, with who should choose each.
How this list works
Grouped, not ranked.
We make one of the products on this list. Tracebrain is a personal memory brain that builds itself from your conversations, in every app you have them: one living profile for every person you talk to, a nightly review of what was decided, promised and paid, and your promises turned into tasks, all in Markdown files you own. That puts it in a group of its own, and it is the only group it is in.
A ranked list of second brains compares things that do different jobs. A notes app cannot know what was said on a call, and a wearable cannot know what was typed in a chat. So this page sorts products by the one question that decides what they can ever remember: what are they built from? Inside each group, each product gets a line on what it captures, what it costs and who should choose it.
Every line was read from the vendor's own page on 22 October 2026. Where a page did not state a price, the list says so rather than guess. Two products we meant to include, ChatGPT's memory and the Friend pendant, are left out because their pages could not be read that day.
The list
Second brains, by what they are built from.
Read on 22 October 2026. Prices in US dollars.
| Product | Built from | Price | Choose it if |
|---|---|---|---|
| Mem | Notes you write | Free; Plus $9 a month; Pro from $29 a month | you want an AI notebook that turns your notes and voice into tasks. |
| Tana | Notes you write | Free; Pro $20 early bird per user a month; Business from $35 | your work happens in meetings and you want notes written during them. |
| Reflect | Notes you write | Free on Mac; iPhone and iPad by subscription, priced in the App Store | you want plain files and a daily note, with AI only when you bring a key. |
| Notion AI | Notes you write | Free and Plus ($10) get a trial of AI; Business $20 per member a month | your team already lives in Notion. |
| Obsidian | Notes you write | Free; Sync from $4 and Publish from $8 a month, billed yearly | you want to own every file and build the system yourself. |
| Recall | Content you save | Free with 10 summaries a month; Plus $10 and Max $38 a month, billed yearly | your problem is the hundred tabs, not the hundred people. |
| Screenpipe | Your screen | Free download; the home page lists no plan prices | you want a searchable record of your whole computer, on your own machine. |
| Littlebird | Your screen | Free tier; Plus $17 and Power $42 a month, billed yearly; Pro from $100 | you want an assistant that already knows what you were working on. |
| Omi | Your voice | $129 device (listed as a limited offer, $179 regular); no subscription required | your important conversations happen in person. |
| Bee | Your voice | Frontier $74.99; some features need Bee Pro, priced off the home page | you want a cheap wearable and do not mind the Amazon account. |
| Kin | What you tell an assistant | Not stated on its site | you want to think out loud with an advisor that remembers you. |
| Memorae | What you tell an assistant | Not stated on its home page | you mostly need reminders that do not get lost. |
| Tracebrain | Your conversations with people | $20 per month, after 7 days free. No free plan | what you lose is what people told you, and what you promised them. |
Read on 22 October 2026 from mem.ai, tana.inc, reflect.app, notion.com, obsidian.md, recall.it, screenpipe.com, littlebird.ai, omi.me, bee.computer, mykin.ai, memorae.ai. A price billed yearly is shown per month, as the vendor shows it.
Built from
Notes you write
The oldest kind of second brain, and still the right one if your thinking happens in writing. The AI works over what you put in: it links, summarises and answers from your own notes. What you never wrote down is not there.
Mem
Notes, voice mode for meetings and spoken thoughts, and email you send to it. From Pro it connects Gmail, Slack or Todoist to find tasks and projects. Price: Free; Plus $9 a month; Pro from $29 a month. Choose it if you want an AI notebook that turns your notes and voice into tasks.
Tana
Meetings first: its own calls and Zoom, Teams and Meet are transcribed, and agents turn them into docs and tasks you approve. The outliner with supertags is now a separate product, Tana Outliner. Price: Free; Pro $20 early bird per user a month; Business from $35. Choose it if your work happens in meetings and you want notes written during them.
Reflect
Daily notes, backlinks, audio memos and web clips, kept as local Markdown files in a folder you choose. AI runs with your own API key. Price: Free on Mac; iPhone and iPad by subscription, priced in the App Store. Choose it if you want plain files and a daily note, with AI only when you bring a key.
Notion AI
Your Notion workspace: pages, databases and, on Business, AI meeting notes and search across connected tools. Price: Free and Plus ($10) get a trial of AI; Business $20 per member a month. Choose it if your team already lives in Notion.
Obsidian
Markdown files on your own disk, linked into a graph. The pricing page lists no AI of its own; AI comes from community plugins. Price: Free; Sync from $4 and Publish from $8 a month, billed yearly. Choose it if you want to own every file and build the system yourself.
Built from
Content you save
A second brain for what you read and watch. It remembers the article, not the person who sent it to you.
Recall
Articles, YouTube videos, podcasts and PDFs you save, summarised and connected to each other. Price: Free with 10 summaries a month; Plus $10 and Max $38 a month, billed yearly. Choose it if your problem is the hundred tabs, not the hundred people.
Built from
Your screen
A recorder that watches what you do on your computer, so nothing has to be saved by hand. It knows everything that crossed the screen, including your chats, but as pixels and text, not as people.
Screenpipe
Screen, audio and app history, kept locally by default in a database you can query through an API or MCP. Price: Free download; the home page lists no plan prices. Choose it if you want a searchable record of your whole computer, on your own machine.
Littlebird
The active window and your meetings, without a bot, plus optional Gmail, Calendar and Outlook. Passwords and banking sites are off limits by default. Price: Free tier; Plus $17 and Power $42 a month, billed yearly; Pro from $100. Choose it if you want an assistant that already knows what you were working on.
Built from
Your voice
A device you wear that listens and transcribes. It captures what is said aloud near it, and nothing that was typed.
Omi
A pendant that transcribes what is said around you, in 25+ languages, into summaries and action items you can search. Price: $129 device (listed as a limited offer, $179 regular); no subscription required. Choose it if your important conversations happen in person.
Bee
A wearable, now sold by Amazon, that turns conversations into summaries and to-dos and learns your relationships over time. Price: Frontier $74.99; some features need Bee Pro, priced off the home page. Choose it if you want a cheap wearable and do not mind the Amazon account.
Built from
What you tell an assistant
An assistant that keeps what you tell it about yourself. Useful, and limited by exactly that: it knows your side, in your words, when you remembered to say it.
Kin
A personal AI advisor with a journal; its memory is built from your sessions with it. Price: Not stated on its site. Choose it if you want to think out loud with an advisor that remembers you.
Memorae
A memory layer for reminders, lists, briefings and context that you hand it. Price: Not stated on its home page. Choose it if you mostly need reminders that do not get lost.
Built from
Your conversations with people
The group none of the others cover. A notes app knows what you wrote about a person; a screen recorder saw their chat go past. Neither keeps the person: who they are, who they mentioned, what you promised each other and whether it was done.
Tracebrain
Reads your one-to-one chats on Telegram and WhatsApp, with the history you already have. Every person gets a note with a profile written from what they said; every night a review records what was decided, promised and paid, and open promises become tasks that close when a later message settles them. It is all Markdown you can download, and an MCP server lets Claude and other assistants read it. Price: $20 per month after a 7-day trial. Choose it if the things you forget arrived in a chat.
Where it loses, plainly. It has no free plan, and several products above do. It reads two messengers and email today: iMessage, Signal, LinkedIn and Slack are not read yet, and nothing said in a meeting or a café reaches it. There is no native phone app; on a phone it is a web app. And it is not a notebook: it does not replace the place where you write your own ideas, which is why the export opens in Obsidian next to the notes you already keep.
How to choose
Three questions, in this order.
What did you last forget?
Not in general: the last time. An idea, an article, a meeting, a promise made in a chat. That is the group to start in.
What will you keep doing?
A notes app works only if you write. A wearable only if you wear it. A recorder or a chat reader asks nothing after setup, which is often the difference between a second brain and an empty one.
Can you take it with you?
Plain files outlive apps. Obsidian, Reflect and Tracebrain's export are Markdown; Screenpipe keeps a local database. Ask any other vendor how you get your memory out before you put years into it.
Most people end up with two: one for their own thinking and one that fills itself. They do not compete. Tracebrain's vault sits next to an Obsidian or Reflect notebook as one more folder of Markdown, and an assistant connected over MCP can read both.
Read further
The rest of the memory brain.
AI second brain
What a second brain built from conversations looks like: a finished profile, a day, MCP, and the vault in Obsidian.
Read more →AI that remembersOne person, one month
Everything it remembers about one invented client after four weeks of chats.
Read more →PricingOne plan, $20 a month
The price, the 7-day trial, who takes the money, and what happens to your vault if you stop paying.
Read more →FAQ
Questions people ask about second brain apps.
What is the best AI second brain app?
The one built from where your memory actually goes missing. If you lose ideas, take a notes app such as Mem, Reflect or Obsidian. If you lose things you read, Recall. If you lose what happened on your computer, Screenpipe or Littlebird. If you lose what was said in person, a wearable such as Omi. If you lose what people told you in chats and what you promised them, that is the gap Tracebrain was built for.
Is there a second brain app that builds itself?
Several build themselves from something: a screen recorder from your screen, a wearable from your voice, Tracebrain from your conversations. What they all skip is the typing. What they differ in is what they can see, so the question to ask is not whether it builds itself, but from what.
Which second brain app reads my Telegram or WhatsApp?
Of the products on this page, Tracebrain is the one built from them: it reads your one-to-one chats on Telegram and WhatsApp and files each conversation under the person it was with. Screen recorders see a chat only while it is on screen. Mem counts a message you send it through WhatsApp, which is a way in, not a reading of your chats.
Is there a free AI second brain?
Yes. Mem, Tana, Notion and Recall have free plans with limits, Obsidian and Reflect on Mac are free, and Screenpipe is a free download. Tracebrain has no free plan: it is $20 per month after a 7-day trial, because every night it sends the day's new messages to a model, and that costs money for every user.
Can I use Obsidian as an AI second brain?
Yes, with AI plugins, and Obsidian is also where Tracebrain's export lands: your vault downloads as a zip of Markdown files that opens as an Obsidian vault. The Obsidian page shows the folder layout and how the two work together.
Why is a vendor's list worth reading?
Read it with that in mind. Most lists of second brain apps are written by a vendor that ranks itself first. This one does not rank at all: it groups products by what they are built from, puts Tracebrain in the one group it belongs to, and says for every other product who should choose it instead. Every price was read from the vendor's own page on 22 October 2026.
Start
If what you forget arrived in a chat.
Connect Telegram or WhatsApp and the first profiles are written from conversations you have already had. A week is enough to see whether it fills a gap the others leave.
$20 per month after 7 days free. A card is taken when the trial starts; cancel before it ends and you pay nothing.