# Reproducing i3 on Mac: From Aerospace to Flashspace > How I landed on a tiling + workspace setup on macOS that actually feels like i3. The journey from Aerospace to Flashspace, and why snappiness matters more than features. - Published: 2026-03-22 - Tags: dx, productivity, tools, setup - URL: https://www.woza.ink/blog/i3-on-mac-flashspace If you've used i3 on Linux, you know the feeling. Workspaces bound to keys. Windows tile automatically. No animations, no transitions, no waiting. You press a key and you're there. Everything else feels slow after that. When I moved to macOS full-time I wanted that back. This is the setup I landed on after trying several approaches — and the one thing I wish someone had told me earlier. --- ## What i3 actually gives you Before jumping into tools, it helps to name what makes i3 great. Tiling is table stakes. The parts that matter are: 1. **Workspaces on a keybind.** `Super+1` takes you to workspace 1. Instantly. No animation, no slide. 2. **Windows follow rules.** Browser goes to workspace 2, terminal to workspace 1, Slack to workspace 4. You don't arrange anything manually. 3. **Keyboard-first everything.** Moving, resizing, focusing — all keys. The mouse is there if you need it, but you shouldn't. The challenge on macOS is that Spaces exist but they're slow, animated, and not really designed for keyboard-driven workflows. Mission Control is a visual picker, not a workspace switcher. --- ## The Aerospace phase [Aerospace](https://github.com/nikitabobko/AeroSpace) was my first attempt. It's a tiling window manager for macOS inspired directly by i3. Tree-based layouts, configurable keybindings, workspace support — the feature list reads like an i3 port. And it works. The tiling is solid. You get i3-style layouts with `tall`, `accordion`, and manual splits. Config is a `.toml` file. The i3 mental model translates. But I ran into friction: **Workspace switching felt heavy.** Aerospace manages its own workspace abstraction on top of macOS Spaces. Switching between workspaces had a noticeable delay — not huge, but enough that it didn't feel like i3. On i3, workspace switching is instant. On Aerospace, there was a beat. **Conflicts with macOS.** Aerospace fights the OS in subtle ways. Stage Manager, fullscreen apps, multi-monitor setups — things would occasionally break or behave unexpectedly. The tool is doing a lot of work to paper over the fact that macOS doesn't want to be a tiling WM. **More than I needed.** I realized I don't actually need full i3-style tiling on Mac. Most of my work happens in a terminal and a browser. What I really needed was fast workspace switching and basic window placement — not a full tree-based layout engine. --- ## Flashspace: the thing that clicked [Flashspace](https://github.com/wojciech-kulik/FlashSpace) is a workspace manager for macOS. Not a tiling window manager — a workspace manager. The distinction matters. It maps keyboard shortcuts directly to macOS Spaces. `Super+1` goes to Space 1. `Super+2` goes to Space 2. No animation. No transition. It's instant in a way that macOS's built-in Space switching is not. The first time I pressed a keybind and was just *there* — no slide, no fade, no delay — I knew this was it. That's the i3 feeling. --- ## What Flashspace does **Instant workspace switching.** This is the core feature and the reason to use it. It disables macOS's Space transition animations and maps each Space to a keyboard shortcut. The switch is effectively zero-latency. **App-to-workspace assignment.** You can configure which apps belong to which Space. Browser on Space 2, terminal on Space 1, communication tools on Space 3. When you switch to a Space, the right apps are focused. **Per-workspace wallpapers.** Minor but useful — each Space can have its own wallpaper. Visual distinction helps you orient instantly after switching. **Lightweight.** Flashspace is a menu bar app. It doesn't manage window layouts, it doesn't override macOS window management, it doesn't fight the OS. It makes Spaces actually usable, and gets out of the way. --- ## My setup Here's my actual configuration: **Space 1 — Terminal.** Ghostty, usually with multiple tmux sessions. This is where the actual work happens. **Space 2 — Browser.** Firefox. Research, docs, PRs, deployed apps. **Space 3 — Communication.** Slack, Discord, email. Isolated from work so it can't steal focus. **Space 4 — Misc.** Finder, system preferences, whatever doesn't have a permanent home. Keybindings: - `Alt+1` through `Alt+4` — switch to Space 1-4 - `Alt+Shift+1` through `Alt+Shift+4` — move the focused window to that Space That's the whole setup. Four workspaces, eight keybindings. --- ## For tiling: pair it with a lightweight tiler Flashspace handles workspaces but not window tiling. If you want windows to snap into place without dragging, pair it with macOS's native tiling (Sequoia added keyboard-driven tiling) or a lightweight tool like [Loop](https://github.com/MrKai77/Loop) for quick half-screen / quarter-screen snapping. I use macOS native tiling for the simple cases (left half, right half) and that's enough. I don't need a tree-based layout engine — I need my terminal on the left and my browser on the right, and I need to switch workspaces instantly. --- ## Why snappiness matters The temptation with window management tools is to chase features. More layout options, more rules, more automation. But the thing that makes i3 great isn't the feature set — it's the speed. You think "I need the browser" and the browser is there. No animation, no waiting, no context switch. Aerospace has more features than Flashspace. It's closer to a full i3 port. But the extra abstraction layer means it can't match the raw speed of Flashspace just making macOS Spaces work properly. The lesson: when you're trying to reproduce a Linux workflow on Mac, optimize for the *feeling* first. Get the speed right, then add complexity only if you need it. I needed fast workspaces. I didn't need a tiling tree. --- ## Getting started 1. Install Flashspace from [GitHub](https://github.com/wojciech-kulik/FlashSpace) or Homebrew 2. Set up 4 macOS Spaces (Mission Control → add desktops) 3. In System Settings → Desktop & Dock, disable "Automatically rearrange Spaces based on most recent use" 4. Configure your keybindings in Flashspace's preferences 5. Assign apps to workspaces 6. Disable macOS Space transition animations if Flashspace hasn't already: ```bash defaults write com.apple.dock workspaces-auto-swoosh -bool NO killall Dock ``` The whole setup takes ten minutes. The speed difference is immediate. ## Notes 1. **context** on "Before jumping into tools, it helps to name what makes i3 great": i3 was created in **2009** by Michael Stapelberg, originally as a response to frustrations with wmii (Window Manager Improved Improved). The name "i3" stands for "improved tiling wm" — improved improved improved. Its design philosophy follows the Unix principle of "do one thing and do it well": i3 manages windows, i3bar handles the status bar, i3lock handles screen locking. The project famously prioritizes documentation and stability over new features. (https://i3wm.org/docs/userguide.html) 2. **quote** on "Keyboard-first everything. Moving, resizing, focusing — all keys": From i3's own documentation: "Only documented behavior is supported. Only add features which benefit many people, instead of going to great lengths to support rarely used workflows." This minimalist philosophy — the project is "generally happy with the feature set" — is what makes i3 feel fast. Every feature carries weight; nothing is there for show. — i3wm project documentation (https://i3wm.org/docs/userguide.html) 3. **source** on "a tiling window manager for macOS inspired directly by i3": AeroSpace deliberately emulates its own virtual workspaces rather than using native macOS Spaces, because macOS Spaces have "considerable limitations" for programmatic control. The design choice means AeroSpace never requires disabling SIP (System Integrity Protection) — a key advantage over **yabai**, macOS's most feature-complete tiling WM, which requires SIP to be disabled for full functionality. (https://github.com/nikitabobko/AeroSpace) 4. **context** on "Workspace switching felt heavy. Aerospace manages its own workspace abstraction on top of macOS Spaces": The macOS tiling WM landscape in 2025-2026: **yabai** is the most feature-complete but requires SIP disabled and frequently loses track of windows on monitor changes. **Amethyst** requires only accessibility permissions but has a steep learning curve. **Rectangle** is the simplest (keyboard-triggered snap zones) but doesn't auto-tile. **AeroSpace** sits in the middle — i3-like tree tiling without SIP, but still in public beta. 5. **source** on "Not a tiling window manager — a workspace manager. The distinction matters": FlashSpace supports two display modes: **Static** (each workspace is assigned to a specific display, like traditional i3) and **Dynamic** (workspaces auto-assign to displays based on where their apps are located, allowing one workspace to span multiple monitors). It also includes Space Control — a grid preview of all workspaces, navigable with 0-9 and arrow keys. (https://github.com/wojciech-kulik/FlashSpace) 6. **context** on "pair it with macOS's native tiling (Sequoia added keyboard-driven tiling)": macOS Sequoia (2024) finally added native keyboard-driven tiling — windows snap to halves and quarters with keyboard shortcuts, no third-party tool required. For most developers who just need terminal-left, browser-right, this eliminates the need for a dedicated tiling WM. The combination of Flashspace (workspaces) + native Sequoia tiling (layout) gives you 80% of the i3 experience with zero external dependencies beyond Flashspace itself. 7. **note** on "the thing that makes i3 great isn't the feature set — it's the speed": Research on perceived latency in UIs suggests that anything under ~100ms feels "instant" to humans, while delays of 200-300ms are perceptible and break the sense of direct manipulation. macOS Space transition animations typically take 300-700ms. Disabling them (which FlashSpace does) doesn't just feel faster — it crosses a perceptual threshold that changes the quality of the interaction from "switching" to "being there."