fontlift

Install, uninstall, list, and clean up fonts on macOS and Windows — from the command line, from Rust, or from Python.

Made by FontLab https://www.fontlab.com/

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What fontlift does

A font is not just a file. To make a font usable by applications, the OS must be told about it: on macOS that means a Core Text registration, on Windows a registry entry plus a GDI call. fontlift handles that mechanics so you don't have to.

Operation	What it does
install	Copy the font file to the OS font directory, register it. Apps see it immediately.
uninstall	Remove the OS registration. File stays on disk.
remove	Unregister and delete the file.
list	Enumerate every face the OS currently knows about.
cleanup	Prune stale registrations + clear font caches.
doctor	Find interrupted operations and resume them.

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Platform support

Platform	Status	Install location (user)	Install location (system)	Admin needed for system?
macOS 12+	Full	~/Library/Fonts/	/Library/Fonts/	sudo
Windows 10 1809+	Full	%LOCALAPPDATA%\Microsoft\Windows\Fonts\	C:\Windows\Fonts\	Administrator
Windows 7–10 pre-1809	System scope only	—	C:\Windows\Fonts\	Administrator
Linux	Planned	~/.local/share/fonts/	/usr/share/fonts/	—

macOS detail: Core Text picks up the font immediately after installation — no reboot, no log-out. /System/Library/Fonts/ is managed by macOS and protected by SIP; fontlift never touches it.

Windows detail: Installation writes both a registry entry under HKCU\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Fonts (user scope) or HKLM\... (system scope) and calls AddFontResourceW + WM_FONTCHANGE so running apps can use the font right away. Without the registry entry the font disappears after the next reboot.

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Font formats

Extension	Format	Notes
.ttf	TrueType	Single face. Most common format.
.otf	OpenType	Single face. PostScript or TrueType outlines.
.ttc / .otc	Collection	Multiple faces in one file (e.g. CJK families).
.woff / .woff2	Web Open Font	Compressed for the web; system support varies.
.dfont	Mac data-fork suitcase	Legacy macOS format.

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CLI quick start

# Install a font for the current user (no admin needed)
fontlift install MyFont.otf

# Install an entire directory of fonts
fontlift install ~/Downloads/InterFamily/

# Install system-wide for all users (requires sudo / admin)
fontlift install --admin MyFont.otf

# List all installed fonts (one path per line, sorted, deduped)
fontlift list
fontlift list --name          # PostScript names instead of paths
fontlift list --path --name   # path::PostScriptName pairs
fontlift list --json          # machine-readable JSON

# Uninstall (keeps the file on disk)
fontlift uninstall ~/Library/Fonts/MyFont.otf
fontlift uninstall --name HelveticaNeue-Bold

# Remove (uninstall + delete the file)
fontlift remove ~/Library/Fonts/OldFont.otf
fontlift remove --name OldFont-Regular

# Prune stale registrations and clear caches
fontlift cleanup
fontlift cleanup --prune-only   # registrations only
fontlift cleanup --cache-only   # caches only
fontlift cleanup --admin        # include system scope

# Preview any operation without changing anything
fontlift --dry-run install MyFont.otf

# Check for and recover interrupted operations
fontlift doctor
fontlift doctor --preview

# Shell completions
fontlift completions bash >> ~/.bashrc
fontlift completions zsh  > ~/.zsh/completions/_fontlift
fontlift completions fish > ~/.config/fish/completions/fontlift.fish

Global flags work with every subcommand:

Flag	Effect
--dry-run	Print what would happen, change nothing
--quiet / -q	Suppress all non-error output
--verbose / -v	Show resolved paths, scope choices, extra detail
--json / -j	Machine-readable JSON output

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Validation

Before installing, fontlift can run an out-of-process validator to catch malformed font files. The validator runs in a separate process so a corrupt font cannot crash fontlift itself.

fontlift install MyFont.ttf                                 # normal (64 MB, 5 s)
fontlift install --validation-strictness lenient Big.ttf    # 128 MB, 10 s
fontlift install --validation-strictness paranoid Untrusted.ttf  # 32 MB, 2 s
fontlift install --no-validate QuickTest.ttf                # skip entirely

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Python

import fontlift

# One-shot helpers
fontlift.install("MyFont.ttf")                    # user scope, no admin
fontlift.install("MyFont.ttf", admin=True)        # system scope
fontlift.uninstall("MyFont.ttf")
fontlift.uninstall(name="HelveticaNeue-Bold")     # by PostScript name
fontlift.remove("OldFont.ttf")
fontlift.cleanup(prune=True, cache=True)
fontlift.cleanup(admin=True)                      # system scope

# List all installed fonts
for font in fontlift.list_fonts():
    # font is a dict; key fields:
    # postscript_name, full_name, family_name, style, path, scope
    print(f"{font['family_name']} {font['style']}  →  {font['path']}")

# Reusable manager (one platform connection, multiple operations)
mgr = fontlift.FontliftManager()
mgr.install_font("/tmp/MyFont.ttf")
faces = mgr.list_fonts()
mgr.cleanup(prune=True, cache=True)

The Python package is a thin wrapper around the fontlift._native PyO3 extension. Build it with maturin develop (development) or maturin build --release (wheel for distribution).

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Rust library

use fontlift_core::{FontManager, FontScope, FontliftFontSource};
use fontlift_platform_mac::MacFontManager; // or WinFontManager on Windows

let manager = MacFontManager::new();
let source = FontliftFontSource::new("MyFont.ttf".into())
    .with_scope(Some(FontScope::User));

manager.install_font(&source)?;

for face in manager.list_installed_fonts()? {
    println!("{}: {} {}", face.source.path.display(), face.family_name, face.style);
}

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Crate layout

fontlift/
├── core/            fontlift-core       types, traits, validation, journal
├── platform-mac/    fontlift-platform-mac   Core Text implementation
├── platform-win/    fontlift-platform-win   Registry + GDI implementation
├── cli/             fontlift-cli        clap-based CLI
├── python/          fontlift-python     PyO3 bindings
└── validator/       fontlift-validator  out-of-process font parser helper

fontlift-core defines FontManager, FontError, FontScope, and the shared data types. Platform crates implement FontManager with real OS calls. The CLI and Python bindings delegate to whichever platform crate is compiled in.

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Building

# Prerequisites: Rust 1.75+, platform SDK (Xcode CLT on macOS, VS Build Tools on Windows)

# Full workspace build + tests
./build.sh --test

# Rust only
cargo build --workspace
cargo test --workspace
cargo clippy --workspace -- -D warnings

# Python wheel (requires maturin)
maturin develop -m python/Cargo.toml          # editable install for dev
maturin build  -m python/Cargo.toml --release # distributable wheel → dist/

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Environment variables

Variable	Effect	Default
FONTLIFT_OVERRIDE_USER_LIBRARY	Override per-user font directory	Platform default
FONTLIFT_OVERRIDE_SYSTEM_LIBRARY	Override system font directory	Platform default
FONTLIFT_DRY_RUN	Simulate all operations	false
FONTLIFT_ALLOW_SYSTEM	Permit system-scope writes	false
FONTLIFT_LOG_LEVEL	trace/debug/info/warn/error	info
FONTLIFT_JOURNAL_PATH	Override crash-recovery journal location	Platform default
RUST_LOG	Standard env_logger filter	—

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Error types

Error	Meaning
FontNotFound	File does not exist at the given path
InvalidFormat	File exists but is not a supported font format
RegistrationFailed	OS refused to register the font
SystemFontProtection	Path is in a system-managed font directory
PermissionDenied	Process lacks the required privileges
AlreadyInstalled	A font with that path is already registered
UnsupportedOperation	Feature not available on this platform

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Roadmap

• Linux support (fontconfig + fc-cache)
• Variable font metadata extraction
• GUI via testypf integration

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License

Apache License 2.0 — see LICENSE.

See CHANGELOG.md for version history.