diff --git a/layers/+lang/ruby/README.org b/layers/+lang/ruby/README.org
index c6dbc803212a..1c84b51868b4 100644
--- a/layers/+lang/ruby/README.org
+++ b/layers/+lang/ruby/README.org
@@ -20,6 +20,7 @@
   - [[#toggles][Toggles]]
   - [[#rake][Rake]]
   - [[#refactor][Refactor]]
+  - [[#seeing-is-believing][Seeing is believing]]
 - [[#layer-options][Layer options]]
 
 * Description
@@ -55,6 +56,7 @@ based on your version manager):
 - =pry= and =pry-doc= are required for *jump to definition* and *code documentation* (=robe-mode=)
 - =ruby_parser= is required for *goto-step_definition* in =feature-mode=
 - =rubocop= is required for rubocop integration
+- =seeing_is_believing= helps you evaluate code inline
 
 You can install the gems in the context of your current project by
 adding them to the =Gemfile=, e.g.:
@@ -210,6 +212,13 @@ When =ruby-test-runner= equals =minitest=.
 | ~SPC m r R c~ | Extract constant       |
 | ~SPC m r R l~ | Extract to let (rspec) |
 
+** Seeing is believing
+
+| Key Binding     | Description                      |
+|-----------------+----------------------------------|
+| ~<SPC> m @ @~   | Run seeing is believing          |
+| ~<SPC> m @ c~   | Clear seeing is believing output |
+
 * Layer options
 
 | Variable                           | Default value | Description                                                                                  |
diff --git a/layers/+lang/ruby/packages.el b/layers/+lang/ruby/packages.el
index 03f2ee9c7d8e..6632c17d77b2 100644
--- a/layers/+lang/ruby/packages.el
+++ b/layers/+lang/ruby/packages.el
@@ -33,6 +33,7 @@
         ruby-test-mode
         ruby-tools
         rvm
+        seeing-is-believing
         smartparens
         rake
         ))
@@ -330,3 +331,18 @@
                 "kr"    'rake-rerun
                 "kR"    'rake-regenerate-cache
                 "kf"    'rake-find-task))))
+
+(defun ruby/init-seeing-is-believing ()
+  (use-package seeing-is-believing
+    :defer t
+    :commands (seeing-is-believing seeing-is-believing-run seeing-is-believing-clear)
+    :if (executable-find "seeing_is_believing")
+    :init
+    (progn
+      (spacemacs|diminish seeing-is-believing " 👁" " @")
+      (dolist (hook '(ruby-mode-hook enh-ruby-mode-hook))
+        (add-hook hook 'seeing-is-believing))
+      (dolist (mode '(ruby-mode enh-ruby-mode))
+        (spacemacs/set-leader-keys-for-major-mode mode
+          "@@" 'seeing-is-believing-run
+          "@c" 'seeing-is-believing-clear)))))