diff --git a/Cargo.lock b/Cargo.lock
index 5b6551603a..e51e1aaaf2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -812,6 +812,24 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "fsevent"
+version = "2.0.2"
+dependencies = [
+ "bitflags",
+ "fsevent-sys",
+ "tempdir",
+]
+
+[[package]]
+name = "fsevent-sys"
+version = "3.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a29c77f1ca394c3e73a9a5d24cfcabb734682d9634fc398f2204a63c994120"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "fuchsia-cprng"
 version = "0.1.1"
@@ -2433,6 +2451,7 @@ dependencies = [
  "crossbeam-channel 0.5.0",
  "dirs",
  "easy-parallel",
+ "fsevent",
  "futures-core",
  "gpui",
  "ignore",
diff --git a/Cargo.toml b/Cargo.toml
index b60e33d042..96be78508c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,5 +1,5 @@
 [workspace]
-members = ["zed", "gpui"]
+members = ["zed", "gpui", "fsevent"]
 
 [patch.crates-io]
 async-task = {git = "https://github.com/zed-industries/async-task", rev = "341b57d6de98cdfd7b418567b8de2022ca993a6e"}
diff --git a/fsevent/Cargo.toml b/fsevent/Cargo.toml
new file mode 100644
index 0000000000..cd7b2f0e7f
--- /dev/null
+++ b/fsevent/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "fsevent"
+version = "2.0.2"
+license = "MIT"
+edition = "2018"
+
+[dependencies]
+bitflags = "1"
+fsevent-sys = "3.0.2"
+
+[dev-dependencies]
+tempdir = "0.3.7"
+
+[package.metadata.docs.rs]
+targets = ["x86_64-apple-darwin"]
diff --git a/fsevent/src/lib.rs b/fsevent/src/lib.rs
new file mode 100644
index 0000000000..09ef812679
--- /dev/null
+++ b/fsevent/src/lib.rs
@@ -0,0 +1,266 @@
+#![cfg(target_os = "macos")]
+
+use bitflags::bitflags;
+use fsevent_sys::{self as fs, core_foundation as cf};
+use std::{
+    convert::AsRef,
+    ffi::{c_void, CStr, OsStr},
+    os::unix::ffi::OsStrExt,
+    path::{Path, PathBuf},
+    slice,
+    sync::mpsc::Sender,
+    time::Duration,
+};
+
+#[derive(Debug)]
+pub struct Event {
+    pub event_id: u64,
+    pub flags: StreamFlags,
+    pub path: PathBuf,
+}
+
+pub struct EventStream {
+    stream: fs::FSEventStreamRef,
+    _sender: Box<Sender<Vec<Event>>>,
+}
+
+unsafe impl Send for EventStream {}
+
+impl EventStream {
+    pub fn new(paths: &[&Path], latency: Duration, event_sender: Sender<Vec<Event>>) -> Self {
+        unsafe {
+            let sender = Box::new(event_sender);
+            let stream_context = fs::FSEventStreamContext {
+                version: 0,
+                info: sender.as_ref() as *const _ as *mut c_void,
+                retain: None,
+                release: None,
+                copy_description: None,
+            };
+
+            let cf_paths =
+                cf::CFArrayCreateMutable(cf::kCFAllocatorDefault, 0, &cf::kCFTypeArrayCallBacks);
+            assert!(!cf_paths.is_null());
+
+            for path in paths {
+                let path_bytes = path.as_os_str().as_bytes();
+                let cf_url = cf::CFURLCreateFromFileSystemRepresentation(
+                    cf::kCFAllocatorDefault,
+                    path_bytes.as_ptr() as *const i8,
+                    path_bytes.len() as cf::CFIndex,
+                    false,
+                );
+                let cf_path = cf::CFURLCopyFileSystemPath(cf_url, cf::kCFURLPOSIXPathStyle);
+                cf::CFArrayAppendValue(cf_paths, cf_path);
+                cf::CFRelease(cf_path);
+                cf::CFRelease(cf_url);
+            }
+
+            let stream = fs::FSEventStreamCreate(
+                cf::kCFAllocatorDefault,
+                callback,
+                &stream_context,
+                cf_paths,
+                fs::kFSEventStreamEventIdSinceNow,
+                latency.as_secs_f64(),
+                fs::kFSEventStreamCreateFlagFileEvents | fs::kFSEventStreamCreateFlagNoDefer,
+            );
+            cf::CFRelease(cf_paths);
+
+            EventStream {
+                stream,
+                _sender: sender,
+            }
+        }
+    }
+
+    pub fn run(self) {
+        unsafe {
+            fs::FSEventStreamScheduleWithRunLoop(
+                self.stream,
+                cf::CFRunLoopGetCurrent(),
+                cf::kCFRunLoopDefaultMode,
+            );
+
+            fs::FSEventStreamStart(self.stream);
+            cf::CFRunLoopRun();
+
+            fs::FSEventStreamFlushSync(self.stream);
+            fs::FSEventStreamStop(self.stream);
+            fs::FSEventStreamRelease(self.stream);
+        }
+    }
+}
+
+extern "C" fn callback(
+    stream_ref: fs::FSEventStreamRef,
+    info: *mut ::std::os::raw::c_void,
+    num: usize,                                 // size_t numEvents
+    event_paths: *mut ::std::os::raw::c_void,   // void *eventPaths
+    event_flags: *const ::std::os::raw::c_void, // const FSEventStreamEventFlags eventFlags[]
+    event_ids: *const ::std::os::raw::c_void,   // const FSEventStreamEventId eventIds[]
+) {
+    unsafe {
+        let event_paths = event_paths as *const *const ::std::os::raw::c_char;
+        let e_ptr = event_flags as *mut u32;
+        let i_ptr = event_ids as *mut u64;
+        let sender = (info as *mut Sender<Vec<Event>>).as_mut().unwrap();
+
+        let paths = slice::from_raw_parts(event_paths, num);
+        let flags = slice::from_raw_parts_mut(e_ptr, num);
+        let ids = slice::from_raw_parts_mut(i_ptr, num);
+
+        let mut events = Vec::with_capacity(num);
+        for p in 0..num {
+            let path_c_str = CStr::from_ptr(paths[p]);
+            let path = PathBuf::from(OsStr::from_bytes(path_c_str.to_bytes()));
+            if let Some(flag) = StreamFlags::from_bits(flags[p]) {
+                events.push(Event {
+                    event_id: ids[p],
+                    flags: flag,
+                    path,
+                });
+            } else {
+                debug_assert!(false, "unknown flag set for fs event: {}", flags[p]);
+            }
+        }
+
+        if sender.send(events).is_err() {
+            fs::FSEventStreamStop(stream_ref);
+            cf::CFRunLoopStop(cf::CFRunLoopGetCurrent());
+        }
+    }
+}
+
+// Synchronize with
+// /System/Library/Frameworks/CoreServices.framework/Versions/A/Frameworks/FSEvents.framework/Versions/A/Headers/FSEvents.h
+bitflags! {
+  #[repr(C)]
+  pub struct StreamFlags: u32 {
+    const NONE = 0x00000000;
+    const MUST_SCAN_SUBDIRS = 0x00000001;
+    const USER_DROPPED = 0x00000002;
+    const KERNEL_DROPPED = 0x00000004;
+    const IDS_WRAPPED = 0x00000008;
+    const HISTORY_DONE = 0x00000010;
+    const ROOT_CHANGED = 0x00000020;
+    const MOUNT = 0x00000040;
+    const UNMOUNT = 0x00000080;
+    const ITEM_CREATED = 0x00000100;
+    const ITEM_REMOVED = 0x00000200;
+    const INODE_META_MOD = 0x00000400;
+    const ITEM_RENAMED = 0x00000800;
+    const ITEM_MODIFIED = 0x00001000;
+    const FINDER_INFO_MOD = 0x00002000;
+    const ITEM_CHANGE_OWNER = 0x00004000;
+    const ITEM_XATTR_MOD = 0x00008000;
+    const IS_FILE = 0x00010000;
+    const IS_DIR = 0x00020000;
+    const IS_SYMLINK = 0x00040000;
+    const OWN_EVENT = 0x00080000;
+    const IS_HARDLINK = 0x00100000;
+    const IS_LAST_HARDLINK = 0x00200000;
+    const ITEM_CLONED = 0x400000;
+  }
+}
+
+impl std::fmt::Display for StreamFlags {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        if self.contains(StreamFlags::MUST_SCAN_SUBDIRS) {
+            let _d = write!(f, "MUST_SCAN_SUBDIRS ");
+        }
+        if self.contains(StreamFlags::USER_DROPPED) {
+            let _d = write!(f, "USER_DROPPED ");
+        }
+        if self.contains(StreamFlags::KERNEL_DROPPED) {
+            let _d = write!(f, "KERNEL_DROPPED ");
+        }
+        if self.contains(StreamFlags::IDS_WRAPPED) {
+            let _d = write!(f, "IDS_WRAPPED ");
+        }
+        if self.contains(StreamFlags::HISTORY_DONE) {
+            let _d = write!(f, "HISTORY_DONE ");
+        }
+        if self.contains(StreamFlags::ROOT_CHANGED) {
+            let _d = write!(f, "ROOT_CHANGED ");
+        }
+        if self.contains(StreamFlags::MOUNT) {
+            let _d = write!(f, "MOUNT ");
+        }
+        if self.contains(StreamFlags::UNMOUNT) {
+            let _d = write!(f, "UNMOUNT ");
+        }
+        if self.contains(StreamFlags::ITEM_CREATED) {
+            let _d = write!(f, "ITEM_CREATED ");
+        }
+        if self.contains(StreamFlags::ITEM_REMOVED) {
+            let _d = write!(f, "ITEM_REMOVED ");
+        }
+        if self.contains(StreamFlags::INODE_META_MOD) {
+            let _d = write!(f, "INODE_META_MOD ");
+        }
+        if self.contains(StreamFlags::ITEM_RENAMED) {
+            let _d = write!(f, "ITEM_RENAMED ");
+        }
+        if self.contains(StreamFlags::ITEM_MODIFIED) {
+            let _d = write!(f, "ITEM_MODIFIED ");
+        }
+        if self.contains(StreamFlags::FINDER_INFO_MOD) {
+            let _d = write!(f, "FINDER_INFO_MOD ");
+        }
+        if self.contains(StreamFlags::ITEM_CHANGE_OWNER) {
+            let _d = write!(f, "ITEM_CHANGE_OWNER ");
+        }
+        if self.contains(StreamFlags::ITEM_XATTR_MOD) {
+            let _d = write!(f, "ITEM_XATTR_MOD ");
+        }
+        if self.contains(StreamFlags::IS_FILE) {
+            let _d = write!(f, "IS_FILE ");
+        }
+        if self.contains(StreamFlags::IS_DIR) {
+            let _d = write!(f, "IS_DIR ");
+        }
+        if self.contains(StreamFlags::IS_SYMLINK) {
+            let _d = write!(f, "IS_SYMLINK ");
+        }
+        if self.contains(StreamFlags::OWN_EVENT) {
+            let _d = write!(f, "OWN_EVENT ");
+        }
+        if self.contains(StreamFlags::IS_LAST_HARDLINK) {
+            let _d = write!(f, "IS_LAST_HARDLINK ");
+        }
+        if self.contains(StreamFlags::IS_HARDLINK) {
+            let _d = write!(f, "IS_HARDLINK ");
+        }
+        if self.contains(StreamFlags::ITEM_CLONED) {
+            let _d = write!(f, "ITEM_CLONED ");
+        }
+        write!(f, "")
+    }
+}
+
+#[test]
+fn test_observe() {
+    use std::{fs, sync::mpsc, time::Duration};
+    use tempdir::TempDir;
+
+    let dir = TempDir::new("test_observe").unwrap();
+    let path = dir.path().canonicalize().unwrap();
+    fs::write(path.join("a"), "a contents").unwrap();
+
+    let (tx, rx) = mpsc::channel();
+    let stream = EventStream::new(&[&path], Duration::from_millis(50), tx);
+    std::thread::spawn(move || stream.run());
+
+    fs::write(path.join("b"), "b contents").unwrap();
+    let events = rx.recv_timeout(Duration::from_millis(500)).unwrap();
+    let event = events.last().unwrap();
+    assert_eq!(event.path, path.join("b"));
+    assert!(event.flags.contains(StreamFlags::ITEM_CREATED));
+
+    fs::remove_file(path.join("a")).unwrap();
+    let events = rx.recv_timeout(Duration::from_millis(500)).unwrap();
+    let event = events.last().unwrap();
+    assert_eq!(event.path, path.join("a"));
+    assert!(event.flags.contains(StreamFlags::ITEM_REMOVED));
+}
diff --git a/zed/Cargo.toml b/zed/Cargo.toml
index 846d6d729e..981f09c2b8 100644
--- a/zed/Cargo.toml
+++ b/zed/Cargo.toml
@@ -19,6 +19,7 @@ crossbeam-channel = "0.5.0"
 dirs = "3.0"
 easy-parallel = "3.1.0"
 futures-core = "0.3"
+fsevent = {path = "../fsevent"}
 gpui = {path = "../gpui"}
 ignore = {git = "https://github.com/zed-industries/ripgrep", rev = "1d152118f35b3e3590216709b86277062d79b8a0"}
 lazy_static = "1.4.0"