diff --git a/modules/feature/eval/autoload/build.el b/modules/feature/eval/autoload/build.el
new file mode 100644
index 000000000..489bf3fdc
--- /dev/null
+++ b/modules/feature/eval/autoload/build.el
@@ -0,0 +1,13 @@
+;;; feature/repl/autoload/build.el
+
+;; TODO
+
+;;;###autoload
+(defun +eval/build ())
+
+;;;###autoload
+(defun +eval/rebuild ())
+
+;;;###autoload
+(defun +eval-get-builder ())
+
diff --git a/modules/feature/eval/autoload/eval.el b/modules/feature/eval/autoload/eval.el
new file mode 100644
index 000000000..edce543d2
--- /dev/null
+++ b/modules/feature/eval/autoload/eval.el
@@ -0,0 +1,70 @@
+;;; feature/repl/autoload/eval.el
+
+;;;###autoload
+(defun +repl/eval-buffer ()
+  "Evaluate the whole buffer."
+  (interactive)
+  (cond ((eq major-mode 'emacs-lisp-mode)
+         (+repl/eval-region (point-min) (point-max)))
+        (t (quickrun))))
+
+;;;###autoload
+(defun +repl/eval-region (beg end)
+  "Evaluate a region and, if large enough, prints its output to a popup buffer (if an
+elisp buffer). Otherwise forward the region to Quickrun."
+  (interactive "r")
+  (let ((load-file-name buffer-file-name))
+    (cond ((eq major-mode 'emacs-lisp-mode)
+           (require 'pp)
+           (let ((result (eval (read (buffer-substring-no-properties beg end))))
+                 lines)
+             (let ((buf (get-buffer-create "*eval*")))
+               (with-current-buffer buf
+                 ;; FIXME messy!
+                 (read-only-mode -1)
+                 (setq-local scroll-margin 0)
+                 (erase-buffer)
+                 (prin1 result buf)
+                 (emacs-lisp-mode)
+                 (pp-buffer)
+                 (read-only-mode 1)
+                 (setq lines (count-lines (point-min) (point-max)))
+                 (goto-char (point-min))
+                 (when (< lines 5)
+                   (message "%s" (buffer-substring (point-min) (point-max)))
+                   (kill-buffer buf)))
+               (unless (< lines 5)
+                 (doom-popup-buffer buf)))))
+          (t (quickrun-region beg end)))))
+
+;;;###autoload
+(defun +repl/eval-region-and-replace (beg end)
+  (interactive "r")
+  (cond ((eq major-mode 'emacs-lisp-mode)
+         (kill-region beg end)
+         (condition-case nil
+             (prin1 (eval (read (current-kill 0)))
+                    (current-buffer))
+           (error (message "Invalid expression")
+                  (insert (current-kill 0)))))
+        (t (quickrun-replace-region beg end))))
+
+
+;;;###autoload (autoload '+repl:eval-region "feature/repl/autoload/repl" nil t)
+;;;###autoload (autoload '+repl:eval-region-and-replace "feature/repl/autoload/eval" nil t)
+
+(@after evil
+   (evil-set-command-properties '+repl/eval-buffer :move-point nil :repeat nil)
+   (evil-set-command-properties '+repl/eval-region :move-point nil :repeat nil)
+
+   (evil-define-operator +repl:eval-region (beg end)
+     "Evaluate a region and, if large enough, prints its output to a popup buffer (if an
+   elisp buffer). Otherwise forward the region to Quickrun."
+     :move-point nil :repeat nil
+     (interactive "<r>")
+     (+repl/eval-region beg end))
+
+   (evil-define-operator +repl:eval-region-and-replace (beg end)
+     (interactive "<r>")
+     (+repl/eval-region-and-replace beg end)))
+
diff --git a/modules/feature/eval/autoload/repl.el b/modules/feature/eval/autoload/repl.el
new file mode 100644
index 000000000..3bccbf71d
--- /dev/null
+++ b/modules/feature/eval/autoload/repl.el
@@ -0,0 +1,45 @@
+;;; feature/repl/autoload/repl.el
+
+;;;###autoload
+(defun +repl/open ()
+  (interactive)
+  ;; TODO
+  (error "Not implemented"))
+
+;;;###autoload
+(defun +repl/send ()
+  (interactive)
+  ;; TODO
+  (error "Not implemented"))
+
+;;;###autoload (autoload '+repl:open "feature/repl/autoload/repl" nil t)
+;;;###autoload (autoload '+repl:send "feature/repl/autoload/repl" nil t)
+
+(@after evil
+  (evil-define-command +repl:open (&optional bang command)
+    :repeat nil
+    (interactive "<!><a>")
+    (if (and doom-repl-buffer (buffer-live-p doom-repl-buffer))
+        (doom-popup-buffer doom-repl-buffer)
+      (rtog/toggle-repl (if (use-region-p) 4))
+      (setq doom-repl-buffer (current-buffer))
+      (when command
+        (with-current-buffer doom-repl-buffer
+          (insert command)
+          (unless bang (comint-send-input))))))
+
+  (evil-define-operator +repl:eval (&optional beg end bang)
+    :type inclusive :repeat nil
+    (interactive "<r><!>")
+    (let ((region-p (use-region-p))
+          (selection (s-trim (buffer-substring-no-properties beg end))))
+      (doom:repl bang)
+      (when (and region-p beg end)
+        (let* ((buf doom-repl-buffer)
+               (win (get-buffer-window buf)))
+          (unless (eq buf (doom-popup-p (get-buffer-window buf)))
+            (doom-popup-buffer buf))
+          (when (and doom-repl-buffer (buffer-live-p doom-repl-buffer))
+            (with-current-buffer doom-repl-buffer
+              (goto-char (point-max))
+              (insert selection))))))))
diff --git a/modules/feature/eval/config.el b/modules/feature/eval/config.el
new file mode 100644
index 000000000..90cc99e1f
--- /dev/null
+++ b/modules/feature/eval/config.el
@@ -0,0 +1,106 @@
+;;; feature/repl/config.el
+
+;; + Running inline code using `quickrun'
+;; + REPLs using `repl-toggle'
+
+(defvar doom-repl-buffer nil
+  "The current REPL buffer.")
+
+(defvar +eval-builders (make-hash-table :test 'equal)
+  "A hash-table of plists, containing functions for building source code. Used
+by `+eval/build', and filled with the `:build' setting")
+
+(defvar +eval--runners nil
+  "A list of `quickrun-add-command' arguments.")
+
+(defvar +eval--repls nil
+  "A list of `rtog/add-repl' arguments.")
+
+;; remove ellipsis when printing sexp in message buffer
+(setq eval-expression-print-length nil
+      eval-expression-print-level  nil)
+
+(@def-setting :repl (mode command)
+  "Define a REPL for a mode. Takes same arguements as `rtog/add-repl'."
+  (if (featurep 'repl-toggle)
+      (list 'rtog/add-repl mode command)
+    `(push ',(list mode command) +eval--repls)))
+
+(@def-setting :build (name mode pred-fn build-fn)
+  "Define a build command function (BUILD-FN) for major-mode MODE, called NAME
+(a symbol). PRED-FN is a predicate function that determines this builder's
+suitability for the current buffer."
+  `(puthash ',(cons name mode)
+            (list :predicate ,pred-fn :fn ,build-fn)
+            +eval-builders))
+
+(@def-setting :eval (name alist &rest plist)
+  "Define a code evaluator for `quickrun'. Takes the same arguments as
+`quickrun-add-command'."
+  (if (featurep 'quickrun)
+      (apply 'quickrun-add-command name alist plist)
+    `(push ',(list name alist plist) +eval--runners)))
+
+
+;;
+;; Packages
+;;
+
+(@def-package quickrun
+  :commands (quickrun
+             quickrun-region
+             quickrun-with-arg
+             quickrun-shell
+             quickrun-compile-only
+             quickrun-replace-region)
+  :init (add-hook 'quickrun/mode-hook 'linum-mode)
+  :config
+  (@set :popup "*quickrun*" :size 10)
+
+  ;; don't auto-focus quickrun windows. Shackle handles that for us.
+  (setq quickrun-focus-p nil)
+
+  (dolist (runner +eval--runners)
+    (apply 'quickrun-add-command runner))
+
+  (defun +repl*quickrun-close-popup (&optional _ _ _ _)
+    "Allows us to re-run quickrun from inside the quickrun buffer (silently)."
+    (awhen (get-buffer-window quickrun/buffer-name)
+      (let (message-log-max)
+        (quickrun/kill-running-process)
+        (message ""))
+      (doom/popup-close it nil)))
+
+  (defun +repl|quickrun-scroll-to-bof ()
+    "Ensures window is scrolled to BOF"
+    (with-selected-window (get-buffer-window quickrun/buffer-name)
+      (goto-char (point-min))))
+
+  ;;; Popup hacks
+  (advice-add 'quickrun :before '+repl*quickrun-close-popup)
+  (advice-add 'quickrun-region :before '+repl*quickrun-close-popup)
+  ;; Ensures window is scrolled to BOF
+  (add-hook 'quickrun-after-run-hook '+repl|quickrun-scroll-to-bof))
+
+
+(@def-package repl-toggle
+  :commands rtog/toggle-repl
+  :preface (defvar rtog/mode-repl-alist nil)
+  :init (@add-hook repl-toggle-mode (evil-initialize-state 'emacs))
+  :config
+  (@set :popup
+    (:custom (lambda (b &rest _)
+               (when (and (featurep 'repl-toggle)
+                          (string-prefix-p "*" (buffer-name (get-buffer b))))
+                 (buffer-local-value 'repl-toggle-mode b))))
+    :popup t :size 16)
+
+  (dolist (repl +eval--repls)
+    (apply 'rtog/add-repl repl))
+
+  (@map :map repl-toggle-mode-map
+        :ei "C-n" 'comint-next-input
+        :ei "C-p" 'comint-previous-input
+        :ei "<down>" 'comint-next-input
+        :ei "<up>"   'comint-previous-input))
+
diff --git a/modules/feature/eval/packages.el b/modules/feature/eval/packages.el
new file mode 100644
index 000000000..fb82835e8
--- /dev/null
+++ b/modules/feature/eval/packages.el
@@ -0,0 +1,6 @@
+;; -*- no-byte-compile: t; -*-
+;;; feature/repl/packages.el
+
+(@package quickrun)
+(@package repl-toggle)
+