Best second brain app for memory and focus

Fortune 500 companies lose £31 billion every year to poor knowledge sharing, often because they rely on scattered tools instead of a second brain app.panopto.com/blog/the-cost-of-not-sharing-knowledge/) to poor knowledge sharing. I read that McKinsey statistic a few months ago and it stopped me cold, because I knew I was part of the problem, especially when using a second brain app.

I have ADHD. My browser has twenty-three tabs open right now. I've bookmarked articles I'll never read, saved links to Slack messages I'll never find again, and had at least four good ideas today that have already vanished because I didn't write them down fast enough.

Sound familiar?

We're all drowning in information. The average professional spends up to 12 hours a week just searching for things they've already seen, unless you use a second brain app. That's not a productivity problem. That's a crisis.

The solution isn't to consume less. It's to remember better personal knowledge management. That's where a second brain app comes in best note taking app adhd.

A second brain app is an external digital system that captures, organises, and retrieves your knowledge so your actual brain doesn't have to hold everything. Think of a second brain app as outsourcing your memory to software that never forgets.

But there are dozens of second brain apps now, and they're all different Notion vs Obsidian. Some want you to build elaborate databases. Others let AI handle everything. Some store your data locally using a second brain app as a Notion alternative. Others live entirely in the cloud.

I've spent years testing these tools, partly for Ultrathink (the capture tool I built) and partly because I genuinely needed a second brain app that worked with my scattered brain. This guide is everything I've learned.

I'll cover what a second brain app actually is, why it matters more than ever in 2026, the key features to look for, and detailed breakdowns of the ten best apps available right now. By the end, you'll know exactly which tool, including a second brain app, fits how you think and work.

Let's find your second brain.

What is a second brain?

The term "second brain" was popularised by Tiago Forte, a productivity consultant who wrote the book Building a Second Brain and advocates using a second brain app.buildingasecondbrain.com/) in 2022. But the concept is simple: it's an external system, a second brain app, where you store everything worth remembering.

Your biological brain is brilliant at making connections, generating ideas, and solving problems; a second brain app mirrors this. It's terrible at storing information reliably. You've experienced this. You read something important, think 'I'll remember that,' and three days later it's gone unless you capture it in a second brain app.

A second brain fixes this. Instead of trusting your memory, you trust a second brain app. Every article you read, idea you have, quote you love, or project note you write goes into one place, a second brain app, where you can find it again.

Forte's methodology includes two frameworks that have become standard in the personal knowledge management world.

PARA is how you organise:

• Projects: Active work with deadlines (launch website, write report)
• Areas: Ongoing responsibilities (health, finances, team management)
• Resources: Topics you're interested in (AI trends, cooking recipes)
• Archives: Completed or inactive items

The key insight is organising by actionability, not by topic. Instead of filing an article under "marketing," a second brain app helps you ask: what project or area does this serve?

CODE is how you work:

• Capture: Save anything that resonates
• Organise: Put it where it's actionable
• Distill: Highlight the key points
• Express: Use it to create something

Most people stop at capture. They save hundreds of bookmarks and never look at them again. Forte calls this the "graveyard of ideas." The goal is to move from a library mindset (collecting) to a factory mindset (producing).

What changed for me: I stopped trying to organise everything perfectly upfront. The best second brain app starts with effortless capture. Get things into the system first. Organise later, when you actually need them.

This is why the tool you choose matters so much. If saving something takes more than a few seconds, you won't do it. And if you can't find things when you need them, the whole system falls apart.

Why you need a second brain in 2026

The information problem has got worse. According to research from McKinsey, 47% of professionals now spend one to five hours every single day just searching for information, a burden a second brain app can help reduce. That's not creating, not thinking, not producing. Just looking for things.

Our brains weren't designed for this. Cognitive science is clear: human working memory can hold roughly four items at a time. Yet we expect ourselves to track dozens of projects, remember hundreds of useful facts, and connect ideas across months of reading and conversation, a task supported by a second brain app.

It doesn't work. We forget most of what we consume within days.

But 2026 is different from previous years for one important reason: AI has changed what's possible.

Gartner predicts that 80% of enterprises will use generative AI in production by the end of this year, up from less than 5% in 2023. That shift is transforming second brain apps from passive storage into active assistants.

The old model was: save things, organise them manually, search when needed. The new model is: save things, let AI organise and connect them, ask questions and get answers from your own knowledge, via a second brain app.

I noticed this change in my own workflow last year with a second brain app. I used to save articles and forget where I put them. Now I can ask my notes "what did I read about pricing strategies?" and get an actual answer, with sources, from things I captured months ago.

This is the real promise of a second brain in 2026. Not just storage. Not just search. But having an AI that knows what you know and helps you use it.

The catch is that AI can only work with what you give it. The most sophisticated retrieval system is useless if you never captured the information in the first place. That's still the hard part, making capture so effortless that you actually do it.

Key features to look for

Not all second brain apps are built the same. Before I walk through specific tools, here are the features that actually matter.

Capture tools

This is where most people's systems fail. If saving something takes more than a few seconds, you won't do it consistently.

Look for: web clippers that work with one click, quick-capture widgets, mobile apps that open fast, voice notes for when you can't type. The fewer steps between "I want to save this" and "it's saved," the better.

I test this with what I call the three-second rule. Can I capture an idea in three seconds or less? If not, my ADHD brain will skip it "just this once" and that idea is gone forever.

Organisation systems

There are three main approaches:

Folders and tags are familiar and work for linear thinkers. Notion does this well.

Bi-directional linking lets you connect notes to each other, building a web of ideas. When you mention a concept, it automatically links to other notes about that concept. Obsidian pioneered this.

AI-powered organisation skips manual filing entirely. You dump things in, and the system figures out where they belong. Mem is the leader here.

Which approach works depends on how your brain works. I'm chaotic, so I prefer minimal manual organisation.

Search and retrieval

Traditional keyword search is table stakes. The question is whether the app offers semantic search, which understands meaning rather than just matching words.

For example, searching "articles about staying focused" should find notes that mention concentration, attention, and deep work, even if they never use the word "focused."

Linking and connections

The magic of a second brain is finding unexpected connections. Some apps show these as graph views, visual maps of how your notes relate. Others surface "related notes" automatically.

I find the automatic approach more useful. I rarely have time to explore a graph view, but seeing relevant notes pop up while I'm writing is genuinely helpful.

Privacy and data ownership

This matters more than people realise. Cloud-only apps mean your data lives on someone else's servers. If they shut down or change pricing, you're stuck.

Local-first apps like Obsidian store files on your own computer. You own them completely. The trade-off is that sync across devices usually costs extra.

Cross-platform availability

Your ideas don't only happen at your desk. A second brain needs to be accessible on your phone, your laptop, and ideally through a browser too.

Check whether the mobile app is fully functional or just a stripped-down viewer. Some apps treat mobile as an afterthought.

Integrations

Does it connect to your other tools? Readwise for highlights, your calendar, task managers like Todoist, read-later apps like Pocket. The more your second brain connects to your existing workflow, the more useful it becomes.

The best second brain apps for 2026

I've tested all of these extensively. Here's what each one actually feels like to use, who it's best for, and what the trade-offs are.

Notion

Best for: Teams and people who love structure

Notion is the most popular second brain app for good reason. It's incredibly flexible. You can build databases, wikis, project trackers, and note systems all in one place.

The block-based editor lets you mix text, tables, images, and embeds freely. Templates help you get started without building everything from scratch. And the collaboration features are excellent if you're working with a team.

What I like: The database functionality is genuinely powerful. I've built CRM systems, content calendars, and reading lists that all link together. Once you understand how relations work, you can create surprisingly sophisticated systems.

What I don't like: Notion can feel overwhelming. There are so many options that you can spend more time tweaking your setup than actually using it. And capture isn't Notion's strength. The web clipper works, but it's not as seamless as dedicated capture tools.

AI features: Notion AI can summarise notes, answer questions, and help with writing. It's integrated directly into the editor.

Pricing: Free tier available with some limits. Plus plan is £8/month.

Obsidian

Best for: Privacy-conscious users who want full control

Obsidian stores everything as plain Markdown files on your own computer. Nothing goes to a server unless you choose to sync it. This makes it the most private option and means you'll never lose access to your notes.

The plugin ecosystem is extraordinary. There are plugins for almost anything you can imagine, from Kanban boards to spaced repetition flashcards. And the graph view, showing how all your notes connect, is genuinely beautiful.

What I like: Bi-directional linking is native and works brilliantly. When I write about a concept, I can link it to related notes with double brackets, and those connections build up into a knowledge graph over time.

What I don't like: There's a learning curve. Obsidian gives you a blank canvas and expects you to figure out your own system. This is powerful but can be paralysing for beginners. And sync costs extra (£4/month) if you want your notes on multiple devices.

AI features: Through community plugins only. There's no native AI, but plugins like Smart Connections add semantic search and AI chat.

Pricing: Free for personal use. Sync is £4/month.

Mem

Best for: People who hate organising

Mem takes a radically different approach. There are no folders. You just dump things in, and the AI figures out how to organise and surface them.

The latest version, Mem 2.0, added offline support and smarter capture tools including voice mode. The AI doesn't just search, it actively connects related mems and can answer questions about your notes.

What I like: The "related mems" feature is genuinely magical. I'll be writing something and Mem surfaces a note I made months ago that's directly relevant. This is what AI-powered knowledge management should feel like.

What I don't like: Everything lives in Mem's cloud. If you're privacy-conscious or worried about vendor lock-in, this might be a dealbreaker. The ecosystem is also smaller than Notion or Obsidian.

AI features: Native and central to the experience. Smart search, automatic organisation, related notes surfacing.

Pricing: Free tier available. Pro is £12/month.

Logseq

Best for: Developers and outliner enthusiasts

Logseq is open-source and stores everything locally, like Obsidian. But where Obsidian uses documents, Logseq uses an outliner structure. Everything is bullet points that can be nested, linked, and rearranged.

This might sound limiting, but it's surprisingly powerful. The outliner format makes it easy to capture thoughts quickly without worrying about structure upfront.

What I like: It's completely free and open-source. Your data is yours. The block-based approach, where every bullet is a block you can reference elsewhere, enables creative workflows that aren't possible in document-based tools.

What I don't like: The interface isn't as polished as commercial alternatives. And because it's open-source, development can feel slower than well-funded competitors.

AI features: Available through plugins, not built in.

Pricing: Free.

Heptabase

Best for: Visual and spatial thinkers

Heptabase is built around infinite whiteboards. Instead of writing in documents, you create cards and arrange them spatially on a canvas. You can cluster related ideas, draw connections, and see your thinking laid out visually.

What I like: If you think in diagrams and spatial relationships, this feels natural in a way text-based tools don't. It's brilliant for research, planning projects, or mapping out complex topics.

What I don't like: The price is higher than most alternatives (£10/month). And if you don't think visually, the whiteboard metaphor might feel forced.

AI features: Growing but not as mature as some competitors.

Pricing: £10/month after trial.

Capacities

Best for: People who think in objects

Capacities has a unique approach: everything is an object. A person is an object. A book is an object. A meeting is an object. Objects have properties and can link to each other.

This sounds abstract, but it's intuitive in practice. When you mention a person in a meeting note, that mention automatically links to the person object, showing all the other notes where they appear.

What I like: The daily notes feature is excellent for journaling and quick capture. The object model makes it easy to build personal CRMs, reading logs, or project databases without the complexity of Notion.

What I don't like: It's a newer platform, so the community and template library are smaller.

AI features: Built-in assistant for search and writing.

Pricing: Free tier available. Pro is £8/month.

Reflect

Best for: Privacy-focused professionals on Apple devices

Reflect combines end-to-end encryption with native AI. Your notes are encrypted so that even Reflect's team can't read them, but GPT-4 can still answer questions about them because the AI runs locally.

What I like: Voice capture is smooth. The daily notes format works well for journaling. And the privacy story is genuinely strong, not just marketing.

What I don't like: It's Apple ecosystem only. No Windows, no Android. And at £12/month, it's one of the more expensive options.

AI features: Native GPT-4 integration with end-to-end encryption.

Pricing: £12/month.

Amplenote

Best for: Getting Things Done practitioners

Amplenote merges notes, tasks, and calendar into one system. Every note can contain tasks. Tasks can be scheduled and prioritised. The calendar shows what you need to do and when.

What I like: The prioritisation system is smart. It weighs urgency, importance, and effort to help you focus on what matters. If you follow GTD methodology, this is purpose-built.

What I don't like: There's a learning curve to use all the features effectively. The interface has a lot going on.

AI features: Integrated for search and writing assistance.

Pricing: Free tier available. Pro is £6/month.

Tana

Best for: Power users who want maximum flexibility

Tana takes the block-based approach further than anyone. Everything is a node. Nodes can have supertags that define their properties. You can build remarkably complex systems once you understand how it works.

What I like: The supertag system is genuinely innovative. You can create structured templates that apply automatically, building personal databases without the overhead of traditional database tools.

What I don't like: Tana is complex. The learning curve is steep. It's still in development and not as stable as mature alternatives. Currently invite-only.

AI features: AI autofill and commands for working with structured data.

Pricing: Free during beta.

AFFiNE

Best for: Notion users who want whiteboard features

AFFiNE combines Notion-style documents with infinite canvas whiteboards in one tool. You can switch between writing mode and canvas mode freely.

It's open-source and local-first, which addresses two of Notion's biggest limitations: privacy and vendor lock-in.

What I like: The hybrid approach is genuinely useful. Some ideas need documents. Some need spatial thinking. Having both in one tool, with your data stored locally, is appealing.

What I don't like: It's newer than established tools, so the ecosystem is smaller and development is still catching up.

AI features: Built-in AI for writing and search.

Pricing: Free. Cloud sync is £5.50/month.

Quick comparison

Here's how all ten apps stack up across the features that matter most:

A few patterns stand out. If privacy matters, Obsidian, Logseq, and AFFiNE store data locally. If you want AI to handle organisation, Mem is the leader. If you need collaboration, Notion is the clear choice. And if budget is tight, Obsidian and Logseq are completely free.

How to choose your second brain app

With ten solid options, the question isn't which app is best. It's which app is best for you. Here's how to narrow it down.

By thinking style

Linear thinkers like structured organisation. If you prefer folders, databases, and clear hierarchies, start with Notion or Amplenote.

Networked thinkers see ideas as connected webs. If you naturally make connections between topics and want to build a knowledge graph, try Obsidian or Logseq.

Visual thinkers need to see ideas spatially. If you sketch diagrams, use whiteboards, or think in maps, Heptabase or AFFiNE will feel more natural.

By use case

For research and learning, Obsidian's linking and Heptabase's visual layouts excel. For team knowledge bases, Notion is the obvious choice. For personal productivity and GTD, Amplenote integrates tasks better than anyone. For quick capture and AI organisation, Mem reduces friction to almost nothing.

By technical comfort

Some apps hand you a blank canvas and expect you to build your own system. Obsidian and Tana reward investment but require it. If you want something that works immediately without configuration, Mem or Capacities are better starting points.

By privacy needs

If you don't want your notes on someone else's servers, your options are Obsidian, Logseq, and AFFiNE (all local-first). Reflect offers a middle ground with end-to-end encryption. Everyone else stores data in their cloud.

The capture test

Here's my real advice: try the capture experience before anything else.

Open the app. Try to save an idea as quickly as possible. Time it. If it takes more than three seconds, you won't use it consistently when you're busy or distracted.

I've abandoned otherwise excellent apps because the capture friction was too high. It doesn't matter how good the features are if you never get ideas into the system.

If capture friction is your bottleneck, consider pairing your second brain with a dedicated capture tool. I built Ultrathink specifically for this problem. It's a browser extension and desktop widget that lets you capture anything in seconds, then sends it to wherever you organise your knowledge.

The best system is often a combination: a fast capture tool for input, and a powerful second brain for organisation and retrieval.

Getting started: your first week

You've picked an app. Now what? Here's how to build momentum without getting lost in setup.

Days 1-2: Choose and install

Pick one app. Just one. Install it on all your devices. Don't spend hours comparing features or reading tutorials. The goal is to start using it.

Set up the bare minimum structure. If you're using PARA, create four folders: Projects, Areas, Resources, Archives. If you prefer something simpler, just start with an inbox folder for everything.

Resist the urge to build elaborate templates or configure every setting. That's procrastination disguised as productivity.

Days 3-4: Focus on capture

Your only goal now is getting things into the system. Aim for ten captures per day. They don't need to be profound. An article you read, a thought you had, a quote you liked, a meeting note.

The point is building the habit. Every time you think "I should remember this," practice capturing it immediately.

I keep my capture tool visible all day. If it takes any effort to find the app, I won't bother when I'm deep in something else.

Days 5-7: Start linking

Once you have a few dozen notes, start connecting them. In most apps, this is as simple as mentioning a topic with double brackets: [[productivity]] or [[project name]].

Don't force connections. Just link naturally when you notice relationships. The graph builds itself over time.

Common mistakes to avoid

Over-organising too early. You don't need a perfect folder structure. Start messy. Organise when you actually need to find things.

Importing everything at once. Don't dump years of bookmarks and old notes into your new system. Start fresh. Import selectively later.

Skipping the weekly review. Set a recurring reminder to spend 15 minutes reviewing what you captured. This is where you distill, connect, and clean up. Without it, your second brain becomes another graveyard.

The goal isn't perfection. It's consistency. A small, well-used second brain beats an elaborate system you abandon after a month.

Conclusion

The best second brain app is the one you'll actually use. Not the one with the most features. Not the one your favourite YouTuber recommends. The one that fits how you think and makes capture effortless enough that you'll do it every day.

My suggestion: try two or three apps for a week each. Focus on the capture experience. See which one sticks.

The tools will keep getting smarter. AI is already transforming these apps from passive storage into active thinking partners. By this time next year, the gap between what your second brain knows and what it can do with that knowledge will shrink even further.

But here's what won't change: the best AI can only work with what you give it. The capture habit remains the foundation. Everything else builds on top.

If you find that capture friction is your biggest obstacle, that's exactly why I built Ultrathink. It's a browser extension and desktop widget designed for people like me who have too many ideas and not enough time to organise them. Capture first, let AI handle the rest.

Whatever tool you choose, start today. Your future self will thank you.