better-fonts

better-fonts is a modular, configurable macOS command-line tool for patching and unpatching Electron and Native macOS applications to use custom fonts.

What It Does

Dual-Driver Architecture: Supports both Electron apps (via preload script CSS injection) and Native Cocoa / Qt / C++ apps (via DYLD_INTERPOSE CoreText hooking).
Custom Font Injection: Intercepts font creation and renders entire user interfaces in your chosen monospace or proportional font.
Bi-directional Patching & Unpatching: Safely applies, replaces, or completely removes font patches without corrupting application bundles.
Native ASAR Engine: Modifies Electron archive packages in-memory, preserving .unpacked native binaries (.node, .dylib, .wasm) without relying on external extraction tools.
Dynamic Native Hooking: Compiles and injects lightweight CoreText interposition dylibs with native launcher wrappers on the fly.
Electron Fuses & macOS Codesigning: Automatically disables EnableEmbeddedAsarIntegrityValidation fuses and re-signs modified .app bundles with ad-hoc signatures.
XDG Base Directory Compliance: Stores user preferences in $XDG_CONFIG_HOME/better-fonts/config.toml (~/.config/better-fonts/config.toml).

Supported Applications

better-fonts includes built-in support for:

Application	Driver	Default Path	Method
Paseo	`electron`	`/Applications/Paseo.app`	Preload CSS (`dist/preload.js`)
Signal	`electron`	`/Applications/Signal.app`	Preload CSS (`preload.bundle.js`)
Slack	`electron`	`/Applications/Slack.app`	Preload CSS (`dist/preload.bundle.js`)
Rekordbox	`native-hook`	`/Applications/rekordbox 7/rekordbox.app`	CoreText Interposition
Engine DJ	`native-hook`	`/Applications/Engine DJ.app`	CoreText Interposition
Telegram	`native-hook`	`/Applications/Telegram.app`	CoreText Interposition

Custom applications can also be declared in config.toml or patched on demand.

How It Works

For everyday users, better-fonts makes font customization on macOS effortless and reversible:

Detects the App Type: Identifies whether the target application is built using web technology (like Slack, Signal, or Paseo) or as a native desktop program (like Rekordbox, Engine DJ, or Telegram).
Injects Your Chosen Font: Seamlessly instructs the application to render its text using your preferred font instead of the hardcoded system default.
Safe and Reversible: Makes changes in an isolated temporary staging area with automatic backups, allowing you to switch fonts at any time or restore the factory original with a single better-fonts unpatch command.

How It Really Works

For developers and technical users, better-fonts operates via two distinct engine drivers tailored to macOS app architectures:

1. Electron Strategy (`electron`)

In-Memory ASAR Manipulation: Parses the 16-byte header and JSON directory tree of the application's app.asar archive directly in Go. It locates the application preload script (such as preload.bundle.js or dist/preload.js), strips any existing patch markers, and injects a DOMContentLoaded event listener that attaches a global CSS style rule (* { font-family: "<font>", monospace !important; }). The ASAR is repacked in-place, preserving .unpacked native modules (.node, .dylib, .wasm) without needing to extract files to disk.
Pure Go Fuse Toggling: Scans the Electron Framework Mach-O binary for the sentinel byte sequence dL7pKGdnNz796PbbjQWNKmHXBZaB9tsX and modifies the EnableEmbeddedAsarIntegrityValidation fuse wire byte directly to '0' (DISABLE), eliminating ASAR integrity checksum verification crashes without external Node.js dependencies.
Bundle Re-Signing: Re-signs the modified bundle with an ad-hoc signature via codesign --force --deep --sign -.

2. Native CoreText Hook Strategy (`native-hook`)

CoreText Interposition (DYLD_INTERPOSE): Dynamically compiles an Objective-C library (libfonthook.dylib) using clang that interposes low-level macOS CoreText creation routines (CTFontCreateWithName and CTFontCreateWithFontDescriptor). When the target app requests fonts, the hook redirects the request to your configured font (with automatic variant mapping for Bold, Heavy, and Semibold weights) while explicitly passing through Apple private system fonts (prefixed with .) and symbol/emoji icon sets.
Launcher Binary Substitution: Renames the original Mach-O executable to <binary>.orig and substitutes a compiled C wrapper launcher (wrapper_launcher). When executed by macOS, the launcher discovers its directory via _NSGetExecutablePath, sets DYLD_INSERT_LIBRARIES=libfonthook.dylib, and calls execv on the original binary, passing through all process arguments and environment variables.
Bundle Re-Signing: Re-signs the modified .app bundle with codesign --force --deep --sign -.

Prerequisites

macOS (Apple Silicon or Intel)
Built-in macOS System Tools (pre-installed on every single Mac out of the box with zero setup required): codesign, osascript, open, and plutil
Xcode Command Line Tools (clang) — only required when patching Native apps like Rekordbox, Engine DJ, or Telegram (install with xcode-select --install)

Note: For Electron applications (Slack, Signal, Paseo), better-fonts is completely self-contained with a native ASAR parser and native Electron fuse manipulator in Go. It works immediately out of the box with zero external dependencies—Node.js, Bun, and npm are not required.

Installation

Go to the Latest Release Page and download the pre-compiled archive for your operating system. Extract and move the binary to your PATH:

tar -xzf better-fonts_*.tar.gz
sudo mv better-fonts /usr/local/bin/

From Source (Optional)

Ensure Go 1.26+ and just are installed:

git clone https://github.com/alexgorbatchev/better-fonts-cli.git
cd better-fonts-cli
just build
cp bin/better-fonts /usr/local/bin/

Quick Start

1. Check Application Status

Inspect all supported applications to see if they are installed, which driver is used, whether they are patched, and what font is currently applied:

better-fonts status

Sample Output:

APP         DRIVER        INSTALLED   PATCHED   CURRENT FONT           PATH
---         ------        ---------   -------   ------------           ----
Paseo       electron      Yes         Yes       Maple Mono Normal NF   /Applications/Paseo.app
Signal      electron      Yes         Yes       SF Mono                /Applications/Signal.app
Slack       electron      Yes         Yes       Maple Mono Normal NF   /Applications/Slack.app
Rekordbox   native-hook   Yes         Yes       Maple Mono Normal NF   /Applications/rekordbox 7/rekordbox.app
Engine DJ   native-hook   Yes         Yes       Maple Mono Normal NF   /Applications/Engine DJ.app
Telegram    native-hook   Yes         No        -                      /Applications/Telegram.app

2. Patch Configured Applications

Patch all applications specified in config.toml (default is all supported apps):

better-fonts patch

3. Patch Specific Applications

Target one or more specific applications by name, ID, or .app bundle path:

better-fonts patch slack
better-fonts patch rekordbox engine-dj telegram
better-fonts patch /Applications/SomeCustomApp.app

4. Override Font from CLI

Apply a specific font without editing the configuration file:

better-fonts patch --font "JetBrains Mono" slack
better-fonts patch --font "Fira Code" telegram

5. Remove Font Patch (Unpatch)

Restore original preload scripts or executables across all or targeted applications:

better-fonts unpatch
better-fonts unpatch rekordbox
better-fonts unpatch /Applications/SomeCustomApp.app

7. Self-Upgrade

Check for and install the latest binary release directly from GitHub:

better-fonts upgrade

8. List Supported Applications

better-fonts list

Configuration

better-fonts reads its configuration from $XDG_CONFIG_HOME/better-fonts/config.toml (defaults to ~/.config/better-fonts/config.toml).

If the configuration file does not exist, running better-fonts creates a default one automatically.

View Configuration Path & Contents

# Print configuration file location
better-fonts config path

# Display current configuration
better-fonts config show

Sample `config.toml`

# Default font applied to patched applications
font = "Maple Mono Normal NF"

# Applications to patch by default.
# Use ["*"] for all supported apps, or list specific IDs: ["slack", "rekordbox", "telegram"]
apps = ["*"]

# Automatically restart applications after patching/unpatching
restart = true

# Per-application overrides
[apps_config.slack]
font = "JetBrains Mono"
restart = true

[apps_config.rekordbox]
font = "Maple Mono Normal NF"

# User-defined custom apps
[[custom_apps]]
id = "custom-electron"
name = "Custom Electron App"
path = "/Applications/CustomElectron.app"
driver = "electron"
process_name = "CustomElectron"
asar_path = "app.asar"
preload_path = "dist/preload.js"

[[custom_apps]]
id = "custom-native"
name = "Custom Native App"
path = "/Applications/CustomNative.app"
driver = "native-hook"
process_name = "CustomNative"

Options & Flags

Global flags apply to all commands:

Flag	Short	Default	Description
`--config`	`-c`	`~/.config/better-fonts/config.toml`	Custom path to configuration TOML file
`--font`	`-f`	(from config)	Override font name
`--app`	`-a`	(from config)	Target specific app(s) (e.g. `-a slack,rekordbox`)
`--restart`		`true`	Restart application after patching or unpatching
`--no-restart`		`false`	Prevent application restart after operations
`--dry-run`		`false`	Simulate actions without modifying disk files
`--verbose`	`-v`	`false`	Enable verbose operational logging
`--version`			Print version string

Development

# Build binary into bin/better-fonts
just build

# Run CLI with arguments
just run status

# Run unit tests with race detection
just test

# Check code hygiene and run vet
just lint

# Clean build artifacts and temporary files
just clean

License

This project is licensed under the MIT License.

Name		Name	Last commit message	Last commit date
.github/workflows		.github/workflows
cmd/better-fonts		cmd/better-fonts
internal		internal
screenshots		screenshots
.gitignore		.gitignore
.goreleaser.yml		.goreleaser.yml
AGENTS.md		AGENTS.md
LICENSE		LICENSE
README.md		README.md
go.mod		go.mod
go.sum		go.sum
justfile		justfile

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better-fonts

What It Does

Supported Applications

How It Works

How It Really Works

1. Electron Strategy (`electron`)

2. Native CoreText Hook Strategy (`native-hook`)

Prerequisites

Installation

From Source (Optional)

Quick Start

1. Check Application Status

2. Patch Configured Applications

3. Patch Specific Applications

4. Override Font from CLI

5. Remove Font Patch (Unpatch)

7. Self-Upgrade

8. List Supported Applications

Configuration

View Configuration Path & Contents

Sample `config.toml`

Options & Flags

Development

License

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better-fonts

What It Does

Supported Applications

How It Works

How It Really Works

1. Electron Strategy (electron)

2. Native CoreText Hook Strategy (native-hook)

Prerequisites

Installation

From Source (Optional)

Quick Start

1. Check Application Status

2. Patch Configured Applications

3. Patch Specific Applications

4. Override Font from CLI

5. Remove Font Patch (Unpatch)

7. Self-Upgrade

8. List Supported Applications

Configuration

View Configuration Path & Contents

Sample config.toml

Options & Flags

Development

License

About

Topics

Resources

Stars

Watchers

Forks

Releases

Contributors

Languages

1. Electron Strategy (`electron`)

2. Native CoreText Hook Strategy (`native-hook`)

Sample `config.toml`