diff --git a/nixos/profiles/common/opt-in/impermanence.nix b/nixos/profiles/common/opt-in/impermanence.nix
index 4d6088c..e3b9531 100644
--- a/nixos/profiles/common/opt-in/impermanence.nix
+++ b/nixos/profiles/common/opt-in/impermanence.nix
@@ -34,6 +34,7 @@
         ".ssh"
 
         ".librewolf"
+        ".thunderbird"
         ".config/chromium"
         ".config/fcitx5"
         ".config/Mumble"
diff --git a/users/guanranwang/home-manager/applications/thunderbird/default.nix b/users/guanranwang/home-manager/applications/thunderbird/default.nix
new file mode 100644
index 0000000..5e8b098
--- /dev/null
+++ b/users/guanranwang/home-manager/applications/thunderbird/default.nix
@@ -0,0 +1,15 @@
+{pkgs, ...}: {
+  programs.thunderbird = {
+    enable = true;
+    profiles.default = {
+      isDefault = true;
+      extraConfig = ''
+        ${builtins.readFile (pkgs.fetchurl {
+          url = "https://raw.githubusercontent.com/HorlogeSkynet/thunderbird-user.js/d6b18302e46349d9924c8a76951bae6efca51501/user.js";
+          hash = "sha256-66B1yLQkQnydAUXD7KGt32OhWSYcdWX+BUozrgW9uAg=";
+        })}
+        ${builtins.readFile ./user-overrides.js}
+      '';
+    };
+  };
+}
diff --git a/users/guanranwang/home-manager/applications/thunderbird/user-overrides.js b/users/guanranwang/home-manager/applications/thunderbird/user-overrides.js
new file mode 100644
index 0000000..eea860c
--- /dev/null
+++ b/users/guanranwang/home-manager/applications/thunderbird/user-overrides.js
@@ -0,0 +1,18 @@
+// Cache related.
+// I have stupidly slow Internet connection and also on a proxy.
+user_pref("browser.cache.disk.enable", true);
+user_pref("browser.cache.memory.enable", true);
+user_pref("browser.cache.memory.capacity", 1);
+user_pref("privacy.clearOnShutdown.cache", false);
+user_pref("mail.imap.use_disk_cache2", true);
+
+
+// View related.
+// Makes messages prettier.
+user_pref("permissions.default.image", 1);
+user_pref("mailnews.display.disallow_mime_handlers", 0);
+user_pref("mailnews.display.html_as", 0);
+user_pref("mailnews.message_display.disable_remote_image", false);
+
+// user_pref("privacy.resistFingerprinting", false);
+user_Pref("mail.shell.checkDefaultClient", false);
\ No newline at end of file
diff --git a/users/guanranwang/nixos/profiles/common/graphical/home/default.nix b/users/guanranwang/nixos/profiles/common/graphical/home/default.nix
index 79fcd96..44a5fdc 100644
--- a/users/guanranwang/nixos/profiles/common/graphical/home/default.nix
+++ b/users/guanranwang/nixos/profiles/common/graphical/home/default.nix
@@ -41,6 +41,7 @@
       "sway"
 
       # Misc
+      "thunderbird"
       "telegram-desktop"
       "nautilus"
       "fcitx5"