diff --git a/lisp/fmt/fmt.el b/lisp/fmt/fmt.el
new file mode 100644
index 0000000..18fe41b
--- /dev/null
+++ b/lisp/fmt/fmt.el
@@ -0,0 +1,76 @@
+;;; fmt.el ---                                       -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2023  John Turner
+
+;; Author: John Turner <notroot@gentoo-pc>
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+(defgroup fmt nil
+  "Format buffers using external programs such as rustfmt.")
+
+(defcustom fmt-executable nil
+  "Formatter executable to use for formatting a buffer."
+  :local t
+  :type '(string)
+  :group 'fmt)
+
+(defcustom fmt-args nil
+  "Args to use when running fmt-executable."
+  :local t
+  :type '(repeat string)
+  :group 'fmt)
+
+(defun fmt--init-output-buffer (name)
+  (with-current-buffer (get-buffer-create name)
+    (erase-buffer)
+    (current-buffer)))
+
+(defun fmt--wait-for-processes (processes)
+  (cl-loop for process in processes
+           do (cl-loop while (accept-process-output process))))
+
+(defun fmt-process-current-buffer ()
+  (let* ((stdout-buffer (fmt--init-output-buffer "*fmt stdout*"))
+         (stderr-buffer (fmt--init-output-buffer "*fmt stderr*"))
+         (stderr (make-pipe-process
+                  :name (format "%s stderr" fmt-executable)
+                  :buffer stderr-buffer
+                  :sentinel 'ignore
+                  :noquery t))
+         (process (make-process
+                   :name fmt-executable
+                   :buffer stdout-buffer
+                   :command (cons fmt-executable fmt-args)
+                   :sentinel 'ignore
+                   :noquery t
+                   :connection-type 'pipe
+                   :stderr stderr)))
+    (process-send-region process (point-min) (point-max))
+    (process-send-eof process)
+    (cons process stderr)))
+
+(defun fmt-current-buffer ()
+  (interactive)
+  (pcase-let ((`(,process . ,stderr) (fmt-process-current-buffer)))
+    (fmt--wait-for-processes (list process stderr))
+    (if (zerop (process-exit-status process))
+        (replace-buffer-contents (process-buffer process))
+      (message "%s failed with exit status %s. See %s for output."
+               fmt-executable
+               (process-exit-status process)
+               (process-buffer stderr)))))
+
+(provide 'fmt)
+;;; fmt.el ends here
diff --git a/lisp/packages.el b/lisp/packages.el
index dbc3d8c..69b201f 100644
--- a/lisp/packages.el
+++ b/lisp/packages.el
@@ -34,3 +34,5 @@
 (use-package best-side-window
   :load-path (lambda () (locate-user-emacs-file "lisp/best-side-window")))
 
+(use-package fmt
+  :load-path (lambda () (locate-user-emacs-file "lisp/fmt")))