Software Alternatives, Accelerators & Startups

TheSecondBrain.dev VS Rectangle

Compare TheSecondBrain.dev VS Rectangle and see what are their differences

TheSecondBrain.dev logo TheSecondBrain.dev

One Brain. Everywhere you work. One memory for Claude, ChatGPT, Cursor and every AI tool you use. Runs in your own Cloudflare account. Open source.

Rectangle logo Rectangle

Window management app based on Spectacle, written in Swift.
Not present

You use AI every day. A year of it should add up to something, and right now it doesn't. Every new chat starts from zero.

Second Brain is a memory layer that runs in your own Cloudflare account. Claude, ChatGPT, Cursor, Windsurf and any other MCP client read and write the same store, so what you work out in one tool is there in the next one.

Getting things in

  • Connect what you already use: Obsidian, Notion (email and calendar ship with 2.1)
  • Save in the moment: Chrome extension, iOS Shortcuts, CLI, REST /capture
  • Or just let the assistant store things as you talk, which is how most of it happens

Getting things back

Recall is semantic, not keyword. Memories link to each other, so a multi-hop search surfaces the reasoning behind a decision, not just the decision.

Entries carry a status (canonical, draft, deprecated) so an agent knows which version of a fact to trust.

Contradictions get flagged for a human to settle instead of quietly overwritten.

Where it lives

Your Cloudflare account: Workers, D1 and Vectorize.

Typical personal use sits inside Cloudflare's free tier. Open source on GitHub. No account with us, and nothing routes through our infrastructure.

Setup

Signed desktop app for Mac and Windows, one-click Cloudflare deploy, or clone the repo and run wrangler.

  • Rectangle Landing page
    Landing page //
    2023-05-20

TheSecondBrain.dev

$ Details
Release Date
2026 May
Startup details
Country
United States
State
GA
Founder(s)
Rahil Pirani

TheSecondBrain.dev features and specs

  • Works with
    Claude, ChatGPT, Cursor, Windsurf, Codex, any MCP client
  • Where it runs
    Your own Cloudflare account (Workers, D1, Vectorize)
  • Recall
    Semantic search with multi-hop graph expansion, not keyword
  • Memory Status
    Entries marked canonical, draft or deprecated so agents know what to trust
  • Contradiction Detection
    Conflicts are flagged for you to settle, never auto-overwritten
  • Capture methods
    Chrome extension, iOS Shortcuts, CLI, REST /capture, MCP tools
  • Integrations
    Obsidian, Notion (email and calendar ship with 2.1)
  • Setup
    Signed Mac and Windows installer, one-click Cloudflare deploy, or wrangler
  • Open Source
    Yes, github.com/rahilp/second-brain-cloudflare
  • Cost
    Typical personal use fits inside Cloudflare's free tier
  • Data Access
    No account with us, nothing routes through our infrastructure

Rectangle features and specs

  • Ease of Use
    Rectangle offers an intuitive user interface that makes window management straightforward and user-friendly.
  • Customizable Shortcuts
    Users can easily configure keyboard shortcuts to better suit their workflow, making window management faster and more efficient.
  • Free
    Rectangle is available for free, making it accessible to anyone without the need for a financial investment.
  • Frequent Updates
    The app receives regular updates, introducing new features and ensuring compatibility with the latest macOS versions.
  • Lightweight
    Rectangle is a lightweight application that doesn't consume many system resources, ensuring smooth performance even on older Macs.

Possible disadvantages of Rectangle

  • Limited Advanced Features
    Rectangle lacks some of the more advanced features found in paid window management applications, such as multiple monitor support and more complex window arrangements.
  • MacOS Only
    Rectangle is only available for macOS, so users of other operating systems are unable to take advantage of its features.
  • Occasional Bugs
    Some users report occasional bugs or unpredictable behavior, which might require troubleshooting or waiting for a future update.
  • Learning Curve for Shortcuts
    While customizable shortcuts are a benefit, there is an initial learning curve for users to memorize and effectively use these shortcuts.
  • Basic Aesthetic
    The app's design and aesthetic are quite basic, lacking the polish and visual appeal found in some other similar tools.

Analysis of Rectangle

Overall verdict

  • Overall, Rectangle is highly regarded for its ease of use, extensive customization options, and the fact that it is free and open-source. It provides essential functionality without unnecessary complexity, making it suitable for both casual users and power users who need efficient window management.

Why this product is good

  • Rectangle is a popular window management tool for macOS, known for its simplicity and ease of use. It allows users to efficiently organize and resize application windows using customizable keyboard shortcuts or by dragging windows into pre-defined areas of the screen. This can enhance productivity by minimizing the time spent arranging windows and improving multitasking capabilities.

Recommended for

    Rectangle is recommended for macOS users looking for a straightforward, lightweight solution to manage application windows. It is particularly beneficial for those who frequently work with multiple applications at once, including developers, designers, and anyone who values a tidy and organized desktop environment.

TheSecondBrain.dev videos

The Same Memory, Across Every Al Tool | Second Brain Demo

More videos:

  • Demo - How to Set Up Second Brain Desktop App in 2 Minutes

Rectangle videos

SKYWALKER RECTANGLE TRAMPOLINE REVIEW!!!

More videos:

  • Review - Skywalker Rectangle Trampoline Review #1
  • Review - Marvin Malton 160 Rectangle Flying Hour Watch Review

Category Popularity

0-100% (relative to TheSecondBrain.dev and Rectangle)
AI Memory
100 100%
0% 0
Mac Tools
0 0%
100% 100
AI
100 100%
0% 0
Window Manager
0 0%
100% 100

Questions & Answers

As answered by people managing TheSecondBrain.dev and Rectangle.

What makes your product unique?

TheSecondBrain.dev's answer

Most AI memory tools store your context on their servers. This one deploys into your own Cloudflare account, so the memory is yours in a literal sense: your database, your vectors, your billing. We can't read it because we never have it.

The other difference is recall:

  • Semantic, not keyword. Ask by meaning, not by remembering what you called it.
  • Multi-hop. Memories link to each other, so a query surfaces the reasoning behind a decision, not just the decision.
  • Status-aware. Entries are marked canonical, draft or deprecated, so an agent knows which version of a fact to trust.
  • Honest about conflicts. When two memories disagree it flags it for you instead of quietly picking a winner.

Why should a person choose your product over its competitors?

TheSecondBrain.dev's answer

It works everywhere you work. Claude, ChatGPT, Cursor, Windsurf, Codex, any MCP client. Most memory tools only remember what happened inside their own app, so you end up with three AI tools holding three different versions of you.

You own the deployment. One-click deploy to Cloudflare, or a signed desktop installer if you'd rather not touch a terminal. Typical personal use sits inside Cloudflare's free tier, so there's no subscription to cancel and no vendor to migrate off later.

It's open source. MIT licensed. Read the code, fork it, extend it. Nothing about how your memory is stored or retrieved is a black box.

How would you describe the primary audience of your product?

TheSecondBrain.dev's answer

People who already live in these tools. They have an Obsidian vault or a Notion workspace, they're in Claude or ChatGPT every day, and some of them are in Cursor too. They're not casual users and they're not necessarily developers. They've built a system, and they've noticed the system doesn't talk to itself.

The shared frustration isn't "AI forgets." It's that a year of real thinking, hours of working through actual problems, hasn't left anything behind. Every conversation is good and then it's gone, and a month later they're figuring out the same thing from scratch.

They also tend to care where their work sits. Not privacy absolutists, just people who'd rather their own thinking accumulate in an account they control than in someone else's product they might have to leave.

What's the story behind your product?

TheSecondBrain.dev's answer

I was using Claude, ChatGPT and Cursor every day and re-explaining the same projects to each of them. A year of that adds up to nothing. The decisions I'd worked out in one tool simply didn't exist in the next one.

I built it for myself first, on Cloudflare because I already had an account and the free tier meant I could run it without thinking about cost. Then I open sourced it, and what people asked for shaped what it became. The desktop app exists because a user on Product Hunt asked for a path that didn't involve a terminal, and she was right to ask.

I still use it every day. Most of the roadmap comes from hitting the limits of my own memory layer.

Which are the primary technologies used for building your product?

TheSecondBrain.dev's answer

  • Cloudflare Workers โ€” runtime
  • Cloudflare D1 โ€” SQLite, entries and relationship graph
  • Cloudflare Vectorize โ€” embeddings and semantic recall
  • Workers AI โ€” embedding generation and synthesis
  • TypeScript
  • Model Context Protocol (MCP) โ€” client integrations
  • Tauri โ€” Mac and Windows desktop app
  • Wrangler + GitHub Actions โ€” deploy and release

Who are some of the biggest customers of your product?

TheSecondBrain.dev's answer

  • People who run Obsidian, Notion and several AI tools side by side
  • Consultants, operators and independent professionals who think out loud with AI all day
  • Writers, researchers and strategists whose best thinking currently lives in chat logs they can't search

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare TheSecondBrain.dev and Rectangle

TheSecondBrain.dev Reviews

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Rectangle Reviews

Best 6 Mac Window Managers
Rectangle shows that you donโ€™t need to dip into your bank account to get window resizer tools. This free Mac window manager lets you manage multiple windows using keyboard shortcuts, menu options, or by dragging and dropping. Just like Magnet, you can split your screen up into quarters, thirds, or halves.
Source: mackeeper.com
Top 6 Window Manager Apps for Mac
Most window manager apps for Mac support multiple monitors. They can help you move windows between screens and create custom layouts for each monitor. Many window manager apps โ€“ such as BetterSnapTool, Magnet, and Rectangle โ€“ offer this functionality.
The 6 Best Mac Window Management Tools
However, it might take some time for you to get used to the shortcuts in the Rectangle app since there are many. Furthermore, you can also add some of your apps to exceptions if you want to keep them away from Rectangle's shortcuts.

Social recommendations and mentions

Based on our record, Rectangle seems to be more popular. It has been mentiond 479 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

TheSecondBrain.dev mentions (0)

We have not tracked any mentions of TheSecondBrain.dev yet. Tracking of TheSecondBrain.dev recommendations started around Jul 2026.

Rectangle mentions (479)

  • Ubuntu 26.04 LTS Released
    As a both old Linux and now decade user of MacOS, after I got used to no middle-click paste and no focus-follows-mouse: 1. Keyboard shortcuts are Emacs, Ctrl-A: start of line, E: end of line, K: kill selected or to end of line, Y to paste, etc. https://support.apple.com/en-au/102650#text 2. Karabiner elements (FOSS) fixes keyboard mappings outside of the Settings: https://karabiner-elements.pqrs.org/ 3. I have the... - Source: Hacker News / 3 months ago
  • Native Instant Space Switching on macOS
    Every macOS user uses Rectangle.app โ€” https://rectangleapp.com The ones who don't use it is because they donโ€™t know it exists. - Source: Hacker News / 4 months ago
  • Native Instant Space Switching on macOS
    I use https://rectangleapp.com/ and enjoy it. I have shortcuts to move windows to the left/right half of the screen, and cycle between monitors. This, combined with native cmd+tab and cmd+` is enough for me. - Source: Hacker News / 4 months ago
  • Make macOS consistently bad (unironically)
    Rectangle [1] is pretty much essential for me because of this. I use only a few keypresses (maximize window, move to one of the halves of the screen horizontally) but that is enough. My mouse very rately interacts with the borders of any window, or those buttons. I had to click on the green one that you mentioned in order to see what it did (yuck). [1] https://rectangleapp.com/. - Source: Hacker News / 4 months ago
  • Make macOS consistently bad (unironically)
    I use Rectangle [1] for window management. I only use three shortcuts: full screen, left half of the screen, and right half of the screen. My editors and chrome are always running in one of these modes. But for other apps like Messages, Notes, Music, etc - yeah I don't usually expand them to full screen. [1] https://rectangleapp.com/. - Source: Hacker News / 4 months ago
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What are some alternatives?

When comparing TheSecondBrain.dev and Rectangle, you can also consider the following products

ChainMemory - Portable, verifiable memory for AI agents โ€” works across ChatGPT, Claude, Gemini and any MCP client

Magnet Window Manager - Magnet Developers

Agentmemory - Persistent memory for Claude Code, Codex & coding agents

yabai - A tiling window manager for macOS based on binary space partitioning

OpenMemory MCP - Your private, local memory layer for all AI tools

BTT Remote - A remote control for you Mac, using your iPhone or iPad