diff --git a/examples/editor-libcosmic/src/main.rs b/examples/editor-libcosmic/src/main.rs
index 0a10124..a28f826 100644
--- a/examples/editor-libcosmic/src/main.rs
+++ b/examples/editor-libcosmic/src/main.rs
@@ -23,7 +23,7 @@ use self::text_box::text_box;
 mod text_box;
 
 lazy_static::lazy_static! {
-    static ref FONT_SYSTEM: FontSystem = FontSystem::new();
+    static ref FONT_SYSTEM: Mutex<FontSystem> = Mutex::new(FontSystem::new());
     static ref SYNTAX_SYSTEM: SyntaxSystem = SyntaxSystem::new();
 }
 
@@ -112,7 +112,8 @@ pub enum Message {
 impl Window {
     pub fn open(&mut self, path: PathBuf) {
         let mut editor = self.editor.lock().unwrap();
-        let mut editor = editor.borrow_with(&FONT_SYSTEM);
+        let mut font_system = FONT_SYSTEM.lock().unwrap();
+        let mut editor = editor.borrow_with(&mut font_system);
         match editor.load_text(&path, self.attrs) {
             Ok(()) => {
                 log::info!("opened '{}'", path.display());
@@ -138,7 +139,7 @@ impl Application for Window {
             .family(cosmic_text::Family::Monospace);
 
         let mut editor = SyntaxEditor::new(
-            Buffer::new(&FONT_SYSTEM, FontSize::Body.to_metrics()),
+            Buffer::new(&FONT_SYSTEM.lock().unwrap(), FontSize::Body.to_metrics()),
             &SYNTAX_SYSTEM,
             "base16-eighties.dark",
         )
@@ -170,11 +171,11 @@ impl Application for Window {
         if let Some(path) = &self.path_opt {
             format!(
                 "COSMIC Text - {} - {}",
-                FONT_SYSTEM.locale(),
+                FONT_SYSTEM.lock().unwrap().locale(),
                 path.display()
             )
         } else {
-            format!("COSMIC Text - {}", FONT_SYSTEM.locale())
+            format!("COSMIC Text - {}", FONT_SYSTEM.lock().unwrap().locale())
         }
     }
 
@@ -240,13 +241,16 @@ impl Application for Window {
                 self.font_size = font_size;
                 let mut editor = self.editor.lock().unwrap();
                 editor
-                    .borrow_with(&FONT_SYSTEM)
+                    .borrow_with(&mut FONT_SYSTEM.lock().unwrap())
                     .buffer_mut()
                     .set_metrics(font_size.to_metrics());
             }
             Message::WrapChanged(wrap) => {
                 let mut editor = self.editor.lock().unwrap();
-                editor.borrow_with(&FONT_SYSTEM).buffer_mut().set_wrap(wrap);
+                editor
+                    .borrow_with(&mut FONT_SYSTEM.lock().unwrap())
+                    .buffer_mut()
+                    .set_wrap(wrap);
             }
             Message::AlignmentChanged(align) => {
                 let mut editor = self.editor.lock().unwrap();
diff --git a/examples/editor-libcosmic/src/text.rs b/examples/editor-libcosmic/src/text.rs
index 2ffc3af..76c1cea 100644
--- a/examples/editor-libcosmic/src/text.rs
+++ b/examples/editor-libcosmic/src/text.rs
@@ -53,7 +53,7 @@ impl Text {
         let mut line = BufferLine::new(string, AttrsList::new(Attrs::new()));
 
         //TODO: do we have to immediately shape?
-        line.shape(&crate::FONT_SYSTEM);
+        line.shape(&FONT_SYSTEM.lock().unwrap());
 
         let text = Self {
             line,
@@ -186,7 +186,7 @@ where
                 };
 
                 cache.with_pixels(
-                    &FONT_SYSTEM,
+                    &FONT_SYSTEM.lock().unwrap(),
                     cache_key,
                     glyph_color,
                     |pixel_x, pixel_y, color| {
diff --git a/examples/editor-libcosmic/src/text_box.rs b/examples/editor-libcosmic/src/text_box.rs
index f98ccfd..a5463e6 100644
--- a/examples/editor-libcosmic/src/text_box.rs
+++ b/examples/editor-libcosmic/src/text_box.rs
@@ -96,7 +96,7 @@ where
         //TODO: allow lazy shape
         let mut editor = self.editor.lock().unwrap();
         editor
-            .borrow_with(&FONT_SYSTEM)
+            .borrow_with(&mut FONT_SYSTEM.lock().unwrap())
             .buffer_mut()
             .shape_until(i32::max_value());
 
@@ -167,7 +167,9 @@ where
 
         let view_w = viewport.width.min(layout.bounds().width) - self.padding.horizontal() as f32;
         let view_h = viewport.height.min(layout.bounds().height) - self.padding.vertical() as f32;
-        let mut editor = editor.borrow_with(&FONT_SYSTEM);
+
+        let mut font_system = FONT_SYSTEM.lock().unwrap();
+        let mut editor = editor.borrow_with(&mut font_system);
 
         editor.buffer_mut().set_size(view_w, view_h);
 
@@ -239,7 +241,8 @@ where
     ) -> Status {
         let state = tree.state.downcast_mut::<State>();
         let mut editor = self.editor.lock().unwrap();
-        let mut editor = editor.borrow_with(&FONT_SYSTEM);
+        let mut font_system = FONT_SYSTEM.lock().unwrap();
+        let mut editor = editor.borrow_with(&mut font_system);
 
         let mut status = Status::Ignored;
         match event {
diff --git a/examples/editor-orbclient/src/main.rs b/examples/editor-orbclient/src/main.rs
index b056c74..396be80 100644
--- a/examples/editor-orbclient/src/main.rs
+++ b/examples/editor-orbclient/src/main.rs
@@ -40,7 +40,7 @@ fn main() {
     )
     .unwrap();
 
-    let font_system = FontSystem::new();
+    let mut font_system = FontSystem::new();
 
     let syntax_system = SyntaxSystem::new();
 
@@ -67,7 +67,7 @@ fn main() {
     #[cfg(feature = "vi")]
     let mut editor = cosmic_text::ViEditor::new(editor);
 
-    let mut editor = editor.borrow_with(&font_system);
+    let mut editor = editor.borrow_with(&mut font_system);
 
     editor
         .buffer_mut()
diff --git a/examples/editor-test/src/main.rs b/examples/editor-test/src/main.rs
index 0f300a4..69a5498 100644
--- a/examples/editor-test/src/main.rs
+++ b/examples/editor-test/src/main.rs
@@ -1,21 +1,20 @@
 // SPDX-License-Identifier: MIT OR Apache-2.0
 
-use cosmic_text::{Action, Buffer, Color, Edit, Editor, FontSystem, Metrics, SwashCache};
+use cosmic_text::{
+    Action, BorrowedWithFontSystem, Buffer, Color, Edit, Editor, FontSystem, Metrics, SwashCache,
+};
 use orbclient::{EventOption, Renderer, Window, WindowFlag};
 use std::{env, fs, process, time::Instant};
 use unicode_segmentation::UnicodeSegmentation;
 
 fn redraw(
     window: &mut Window,
-    editor: &mut Editor,
-    font_system: &FontSystem,
+    editor: &mut BorrowedWithFontSystem<Editor>,
     swash_cache: &mut SwashCache,
 ) {
     let bg_color = orbclient::Color::rgb(0x34, 0x34, 0x34);
     let font_color = Color::rgb(0xFF, 0xFF, 0xFF);
 
-    let mut editor = editor.borrow_with(font_system);
-
     editor.shape_as_needed();
     if editor.buffer().redraw() {
         let instant = Instant::now();
@@ -39,7 +38,7 @@ fn main() {
     env_logger::init();
 
     let display_scale = 1.0;
-    let font_system = FontSystem::new();
+    let mut font_system = FontSystem::new();
 
     let mut window = Window::new_flags(
         -1,
@@ -63,12 +62,12 @@ fn main() {
 
     let mut buffer = Buffer::new(&font_system, font_sizes[font_size_default]);
     buffer
-        .borrow_with(&font_system)
+        .borrow_with(&mut font_system)
         .set_size(window.width() as f32, window.height() as f32);
 
     let mut editor = Editor::new(buffer);
 
-    let mut editor = editor.borrow_with(&font_system);
+    let mut editor = editor.borrow_with(&mut font_system);
 
     let mut swash_cache = SwashCache::new();
 
@@ -139,7 +138,7 @@ fn main() {
         // Finally, normal enter
         editor.action(Action::Enter);
 
-        redraw(&mut window, &mut editor, &font_system, &mut swash_cache);
+        redraw(&mut window, &mut editor, &mut swash_cache);
 
         for event in window.events() {
             if let EventOption::Quit(_) = event.to_option() {
diff --git a/examples/rich-text/src/main.rs b/examples/rich-text/src/main.rs
index a3e6be8..e8e8213 100644
--- a/examples/rich-text/src/main.rs
+++ b/examples/rich-text/src/main.rs
@@ -13,7 +13,7 @@ use std::{
 fn main() {
     env_logger::init();
 
-    let font_system = FontSystem::new();
+    let mut font_system = FontSystem::new();
 
     let display_scale = match orbclient::get_display_size() {
         Ok((w, h)) => {
@@ -41,7 +41,7 @@ fn main() {
         Metrics::new(32.0, 44.0).scale(display_scale),
     ));
 
-    let mut editor = editor.borrow_with(&font_system);
+    let mut editor = editor.borrow_with(&mut font_system);
 
     editor
         .buffer_mut()
diff --git a/examples/terminal/src/main.rs b/examples/terminal/src/main.rs
index 2069ba7..eae3ffe 100644
--- a/examples/terminal/src/main.rs
+++ b/examples/terminal/src/main.rs
@@ -6,7 +6,7 @@ use termion::{color, cursor};
 
 fn main() {
     // A FontSystem provides access to detected system fonts, create one per application
-    let font_system = FontSystem::new();
+    let mut font_system = FontSystem::new();
 
     // A SwashCache stores rasterized glyphs, create one per application
     let mut swash_cache = SwashCache::new();
@@ -17,7 +17,7 @@ fn main() {
     // A Buffer provides shaping and layout for a UTF-8 string, create one per text widget
     let mut buffer = Buffer::new(&font_system, metrics);
 
-    let mut buffer = buffer.borrow_with(&font_system);
+    let mut buffer = buffer.borrow_with(&mut font_system);
 
     // Set a size for the text buffer, in pixels
     let width = 80u16;
diff --git a/src/buffer.rs b/src/buffer.rs
index 4dbef2a..937a60b 100644
--- a/src/buffer.rs
+++ b/src/buffer.rs
@@ -335,7 +335,7 @@ impl Buffer {
 
     pub fn borrow_with<'a>(
         &'a mut self,
-        font_system: &'a FontSystem,
+        font_system: &'a mut FontSystem,
     ) -> BorrowedWithFontSystem<'a, Buffer> {
         BorrowedWithFontSystem {
             inner: self,
diff --git a/src/edit/mod.rs b/src/edit/mod.rs
index 06a06db..b7ddee8 100644
--- a/src/edit/mod.rs
+++ b/src/edit/mod.rs
@@ -81,7 +81,7 @@ pub enum Action {
 pub trait Edit {
     fn borrow_with<'a>(
         &'a mut self,
-        font_system: &'a FontSystem,
+        font_system: &'a mut FontSystem,
     ) -> BorrowedWithFontSystem<'a, Self>
     where
         Self: Sized,
diff --git a/src/font/system/mod.rs b/src/font/system/mod.rs
index e508e1f..2a87474 100644
--- a/src/font/system/mod.rs
+++ b/src/font/system/mod.rs
@@ -15,7 +15,7 @@ pub use fontdb;
 
 pub struct BorrowedWithFontSystem<'a, T> {
     pub(crate) inner: &'a mut T,
-    pub(crate) font_system: &'a FontSystem,
+    pub(crate) font_system: &'a mut FontSystem,
 }
 
 impl<'a, T> Deref for BorrowedWithFontSystem<'a, T> {
diff --git a/src/shape.rs b/src/shape.rs
index cb6039c..4cc0346 100644
--- a/src/shape.rs
+++ b/src/shape.rs
@@ -35,7 +35,7 @@ fn shape_fallback(
     let rtl = matches!(buffer.direction(), rustybuzz::Direction::RightToLeft);
     assert_eq!(rtl, span_rtl);
 
-    let glyph_buffer = rustybuzz::shape(&font.rustybuzz(), &[], buffer);
+    let glyph_buffer = rustybuzz::shape(font.rustybuzz(), &[], buffer);
     let glyph_infos = glyph_buffer.glyph_infos();
     let glyph_positions = glyph_buffer.glyph_positions();