diff --git a/build.zig b/build.zig
index 310531b..023f96f 100644
--- a/build.zig
+++ b/build.zig
@@ -143,8 +143,10 @@ pub fn build(b: *std.Build) void {
             .{ .name = "log", .module = log_mod },
             .{ .name = "cbor", .module = cbor_mod },
             .{ .name = "thespian", .module = thespian_mod },
+            .{ .name = "Buffer", .module = Buffer_mod },
             .{ .name = "tracy", .module = tracy_mod },
             .{ .name = "syntax", .module = syntax_dep.module("syntax") },
+            .{ .name = "dizzy", .module = dizzy_dep.module("dizzy") },
         },
     });
 
diff --git a/src/LSP.zig b/src/LSP.zig
index 0bc1912..1d9e14f 100644
--- a/src/LSP.zig
+++ b/src/LSP.zig
@@ -35,7 +35,11 @@ pub fn send_notification(self: Self, method: []const u8, m: anytype) tp.result {
     var cb = std.ArrayList(u8).init(self.a);
     defer cb.deinit();
     cbor.writeValue(cb.writer(), m) catch |e| return tp.exit_error(e);
-    return self.pid.send(.{ "NTFY", method, cb.items });
+    return self.send_notification_raw(method, cb.items);
+}
+
+pub fn send_notification_raw(self: Self, method: []const u8, cb: []const u8) tp.result {
+    return self.pid.send(.{ "NTFY", method, cb });
 }
 
 pub fn close(self: *Self) void {
diff --git a/src/Project.zig b/src/Project.zig
index 20a34eb..2499b09 100644
--- a/src/Project.zig
+++ b/src/Project.zig
@@ -2,6 +2,8 @@ const std = @import("std");
 const tp = @import("thespian");
 const cbor = @import("cbor");
 const root = @import("root");
+const dizzy = @import("dizzy");
+const Buffer = @import("Buffer");
 const builtin = @import("builtin");
 
 const LSP = @import("LSP.zig");
@@ -185,6 +187,129 @@ pub fn did_open(self: *Self, from: tp.pid_ref, file_path: []const u8, file_type:
     });
 }
 
+pub fn did_change(self: *Self, file_path: []const u8, version: usize, root_dst_addr: usize, root_src_addr: usize) !void {
+    const lsp = try self.get_file_lsp(file_path);
+    const uri = self.make_URI(file_path) catch |e| return tp.exit_error(e);
+    defer self.a.free(uri);
+
+    const root_dst: Buffer.Root = if (root_dst_addr == 0) return else @ptrFromInt(root_dst_addr);
+    const root_src: Buffer.Root = if (root_src_addr == 0) return else @ptrFromInt(root_src_addr);
+
+    var dizzy_edits = std.ArrayListUnmanaged(dizzy.Edit){};
+    var dst = std.ArrayList(u8).init(self.a);
+    var src = std.ArrayList(u8).init(self.a);
+    var scratch = std.ArrayListUnmanaged(u32){};
+    var edits_cb = std.ArrayList(u8).init(self.a);
+    const writer = edits_cb.writer();
+
+    defer {
+        edits_cb.deinit();
+        dst.deinit();
+        src.deinit();
+        scratch.deinit(self.a);
+        dizzy_edits.deinit(self.a);
+    }
+
+    try root_dst.store(dst.writer());
+    try root_src.store(src.writer());
+
+    const scratch_len = 4 * (dst.items.len + src.items.len) + 2;
+    try scratch.ensureTotalCapacity(self.a, scratch_len);
+    scratch.items.len = scratch_len;
+
+    try dizzy.PrimitiveSliceDiffer(u8).diff(self.a, &dizzy_edits, src.items, dst.items, scratch.items);
+
+    var lines_dst: usize = 0;
+    var pos_src: usize = 0;
+    var pos_dst: usize = 0;
+    var last_offset: usize = 0;
+    var edits_count: usize = 0;
+
+    for (dizzy_edits.items) |dizzy_edit| {
+        switch (dizzy_edit.kind) {
+            .equal => {
+                const dist = dizzy_edit.range.end - dizzy_edit.range.start;
+                pos_src += dist;
+                pos_dst += dist;
+                scan_char(src.items[dizzy_edit.range.start..dizzy_edit.range.end], &lines_dst, '\n', &last_offset);
+            },
+            .insert => {
+                const dist = dizzy_edit.range.end - dizzy_edit.range.start;
+                pos_src += 0;
+                pos_dst += dist;
+                const line_start_dst: usize = lines_dst;
+                scan_char(dst.items[dizzy_edit.range.start..dizzy_edit.range.end], &lines_dst, '\n', null);
+                try cbor.writeValue(writer, .{
+                    .range = .{
+                        .start = .{ .line = line_start_dst, .character = last_offset },
+                        .end = .{ .line = line_start_dst, .character = last_offset },
+                    },
+                    .text = dst.items[dizzy_edit.range.start..dizzy_edit.range.end],
+                });
+                edits_count += 1;
+            },
+            .delete => {
+                const dist = dizzy_edit.range.end - dizzy_edit.range.start;
+                pos_src += dist;
+                pos_dst += 0;
+                var line_end_dst: usize = lines_dst;
+                var offset_end_dst: usize = last_offset;
+                scan_char(src.items[dizzy_edit.range.start..dizzy_edit.range.end], &line_end_dst, '\n', &offset_end_dst);
+                if (lines_dst == line_end_dst) offset_end_dst = last_offset + dist;
+                try cbor.writeValue(writer, .{
+                    .range = .{
+                        .start = .{ .line = lines_dst, .character = last_offset },
+                        .end = .{ .line = line_end_dst, .character = offset_end_dst },
+                    },
+                    .text = "",
+                });
+                edits_count += 1;
+            },
+        }
+    }
+
+    var msg = std.ArrayList(u8).init(self.a);
+    defer msg.deinit();
+    const msg_writer = msg.writer();
+    try cbor.writeMapHeader(msg_writer, 2);
+    try cbor.writeValue(msg_writer, "textDocument");
+    try cbor.writeValue(msg_writer, .{ .uri = uri, .version = version });
+    try cbor.writeValue(msg_writer, "contentChanges");
+    try cbor.writeArrayHeader(msg_writer, edits_count);
+    _ = try msg_writer.write(edits_cb.items);
+
+    try lsp.send_notification_raw("textDocument/didChange", msg.items);
+}
+
+fn scan_char(chars: []const u8, lines: *usize, char: u8, last_offset: ?*usize) void {
+    var pos = chars;
+    while (pos.len > 0) {
+        if (pos[0] == char) {
+            if (last_offset) |off| off.* = pos.len - 1;
+            lines.* += 1;
+        }
+        pos = pos[1..];
+    }
+}
+
+pub fn did_save(self: *Self, file_path: []const u8) tp.result {
+    const lsp = try self.get_file_lsp(file_path);
+    const uri = self.make_URI(file_path) catch |e| return tp.exit_error(e);
+    defer self.a.free(uri);
+    try lsp.send_notification("textDocument/didSave", .{
+        .textDocument = .{ .uri = uri },
+    });
+}
+
+pub fn did_close(self: *Self, file_path: []const u8) tp.result {
+    const lsp = try self.get_file_lsp(file_path);
+    const uri = self.make_URI(file_path) catch |e| return tp.exit_error(e);
+    defer self.a.free(uri);
+    try lsp.send_notification("textDocument/didClose", .{
+        .textDocument = .{ .uri = uri },
+    });
+}
+
 pub fn goto_definition(self: *Self, from: tp.pid_ref, file_path: []const u8, row: usize, col: usize) !void {
     const lsp = try self.get_file_lsp(file_path);
     const uri = self.make_URI(file_path) catch |e| return tp.exit_error(e);
diff --git a/src/project_manager.zig b/src/project_manager.zig
index 76a3a4b..7fc6526 100644
--- a/src/project_manager.zig
+++ b/src/project_manager.zig
@@ -67,6 +67,27 @@ pub fn did_open(file_path: []const u8, file_type: *const FileType, version: usiz
     return (try get()).pid.send(.{ "did_open", project, file_path, file_type.name, file_type.language_server, version, text_ptr, text.len });
 }
 
+pub fn did_change(file_path: []const u8, version: usize, root_dst: usize, root_src: usize) tp.result {
+    const project = tp.env.get().str("project");
+    if (project.len == 0)
+        return tp.exit("No project");
+    return (try get()).pid.send(.{ "did_change", project, file_path, version, root_dst, root_src });
+}
+
+pub fn did_save(file_path: []const u8) tp.result {
+    const project = tp.env.get().str("project");
+    if (project.len == 0)
+        return tp.exit("No project");
+    return (try get()).pid.send(.{ "did_save", project, file_path });
+}
+
+pub fn did_close(file_path: []const u8) tp.result {
+    const project = tp.env.get().str("project");
+    if (project.len == 0)
+        return tp.exit("No project");
+    return (try get()).pid.send(.{ "did_close", project, file_path });
+}
+
 pub fn goto_definition(file_path: []const u8, row: usize, col: usize) tp.result {
     const project = tp.env.get().str("project");
     if (project.len == 0)
@@ -146,6 +167,9 @@ const Process = struct {
         var text_ptr: usize = 0;
         var text_len: usize = 0;
 
+        var root_dst: usize = 0;
+        var root_src: usize = 0;
+
         if (try m.match(.{ "walk_tree_entry", tp.extract(&project_directory), tp.extract(&path), tp.extract(&high), tp.extract(&low) })) {
             const mtime = (@as(i128, @intCast(high)) << 64) | @as(i128, @intCast(low));
             if (self.projects.get(project_directory)) |project|
@@ -173,6 +197,12 @@ const Process = struct {
         } else if (try m.match(.{ "did_open", tp.extract(&project_directory), tp.extract(&path), tp.extract(&file_type), tp.extract_cbor(&language_server), tp.extract(&version), tp.extract(&text_ptr), tp.extract(&text_len) })) {
             const text = if (text_len > 0) @as([*]const u8, @ptrFromInt(text_ptr))[0..text_len] else "";
             self.did_open(from, project_directory, path, file_type, language_server, version, text) catch |e| return from.forward_error(e);
+        } else if (try m.match(.{ "did_change", tp.extract(&project_directory), tp.extract(&path), tp.extract(&version), tp.extract(&root_dst), tp.extract(&root_src) })) {
+            self.did_change(project_directory, path, version, root_dst, root_src) catch |e| return from.forward_error(e);
+        } else if (try m.match(.{ "did_save", tp.extract(&project_directory), tp.extract(&path) })) {
+            self.did_save(project_directory, path) catch |e| return from.forward_error(e);
+        } else if (try m.match(.{ "did_close", tp.extract(&project_directory), tp.extract(&path) })) {
+            self.did_close(project_directory, path) catch |e| return from.forward_error(e);
         } else if (try m.match(.{ "goto_definition", tp.extract(&project_directory), tp.extract(&path), tp.extract(&row), tp.extract(&col) })) {
             self.goto_definition(from, project_directory, path, row, col) catch |e| return from.forward_error(e);
         } else if (try m.match(.{ "get_mru_position", tp.extract(&project_directory), tp.extract(&path) })) {
@@ -221,6 +251,27 @@ const Process = struct {
         return project.did_open(from, file_path, file_type, language_server, version, text);
     }
 
+    fn did_change(self: *Process, project_directory: []const u8, file_path: []const u8, version: usize, root_dst: usize, root_src: usize) tp.result {
+        const frame = tracy.initZone(@src(), .{ .name = module_name ++ ".did_change" });
+        defer frame.deinit();
+        const project = if (self.projects.get(project_directory)) |p| p else return tp.exit("No project");
+        return project.did_change(file_path, version, root_dst, root_src) catch |e| tp.exit_error(e);
+    }
+
+    fn did_save(self: *Process, project_directory: []const u8, file_path: []const u8) tp.result {
+        const frame = tracy.initZone(@src(), .{ .name = module_name ++ ".did_save" });
+        defer frame.deinit();
+        const project = if (self.projects.get(project_directory)) |p| p else return tp.exit("No project");
+        return project.did_save(file_path);
+    }
+
+    fn did_close(self: *Process, project_directory: []const u8, file_path: []const u8) tp.result {
+        const frame = tracy.initZone(@src(), .{ .name = module_name ++ ".did_close" });
+        defer frame.deinit();
+        const project = if (self.projects.get(project_directory)) |p| p else return tp.exit("No project");
+        return project.did_close(file_path);
+    }
+
     fn goto_definition(self: *Process, from: tp.pid_ref, project_directory: []const u8, file_path: []const u8, row: usize, col: usize) tp.result {
         const frame = tracy.initZone(@src(), .{ .name = module_name ++ ".goto_definition" });
         defer frame.deinit();
diff --git a/src/tui/editor.zig b/src/tui/editor.zig
index f8ac4ed..2e3e339 100644
--- a/src/tui/editor.zig
+++ b/src/tui/editor.zig
@@ -385,6 +385,8 @@ pub const Editor = struct {
         self.plane.home();
         self.plane.context().cursor_disable() catch {};
         _ = try self.handlers.msg(.{ "E", "close" });
+        if (self.syntax) |_| if (self.file_path) |file_path|
+            project_manager.did_close(file_path) catch {};
     }
 
     fn save(self: *Self) !void {
@@ -973,8 +975,10 @@ pub const Editor = struct {
         const dirty = if (self.buffer) |buf| buf.is_dirty() else false;
 
         const root: ?Buffer.Root = self.buf_root() catch null;
-        if (token_from(self.last.root) != token_from(root))
+        if (token_from(self.last.root) != token_from(root)) {
             try self.send_editor_update(self.last.root, root);
+            self.lsp_version += 1;
+        }
 
         if (self.last.dirty != dirty)
             try self.send_editor_dirty(dirty);
@@ -1069,6 +1073,7 @@ pub const Editor = struct {
 
     fn send_editor_save(self: *const Self, file_path: []const u8) !void {
         _ = try self.handlers.msg(.{ "E", "save", file_path });
+        if (self.syntax) |_| project_manager.did_save(file_path) catch {};
     }
 
     fn send_editor_dirty(self: *const Self, file_dirty: bool) !void {
@@ -1081,6 +1086,8 @@ pub const Editor = struct {
 
     fn send_editor_update(self: *const Self, old_root: ?Buffer.Root, new_root: ?Buffer.Root) !void {
         _ = try self.handlers.msg(.{ "E", "update", token_from(new_root), token_from(old_root) });
+        if (self.syntax) |_| if (self.file_path) |file_path|
+            project_manager.did_change(file_path, self.lsp_version, token_from(new_root), token_from(old_root)) catch {};
     }
 
     fn clamp_abs(self: *Self, abs: bool) void {