diff --git a/docs/api.org b/docs/api.org
index 42f11fb41..20ba9fa90 100644
--- a/docs/api.org
+++ b/docs/api.org
@@ -30,6 +30,58 @@ It is integrated into Helpful, in Doom.
     ...))
 #+END_SRC
 
+* custom-theme-set-faces!
+#+BEGIN_SRC elisp :eval no
+(custom-theme-set-faces! 'doom-one-theme
+ `(outline-1 :weight normal)
+ `(outline-2 :weight normal)
+ `(outline-3 :weight normal)
+ `(outline-4 :weight normal)
+ `(outline-5 :weight normal)
+ `(outline-6 :weight normal)
+ `(default :background "red" :weight bold)
+ `(region :background "red" :weight bold)`)
+
+(custom-theme-set-faces! '(doom-one-theme doom-one-light-theme)
+ `((outline-1 outline-2 outline-3 outline-4 outline-5 outline-6)
+   :weight normal)
+ `((default region)
+   :background "red" :weight bold))
+
+(let ((red-bg-faces '(default region)))
+  (custom-theme-set-faces! '(doom-one-theme doom-one-light-theme)
+   `(,(cl-loop for i from 0 to 6 collect (intern (format "outline-%d" i)))
+     :weight normal)
+   `(,red-bg-faces
+     :background "red" :weight bold)))
+#+END_SRC
+
+* custom-set-faces!
+#+BEGIN_SRC elisp :eval no
+(custom-set-faces!
+ `(outline-1 :weight normal)
+ `(outline-2 :weight normal)
+ `(outline-3 :weight normal)
+ `(outline-4 :weight normal)
+ `(outline-5 :weight normal)
+ `(outline-6 :weight normal)
+ `(default :background "red" :weight bold)
+ `(region :background "red" :weight bold)`)
+
+(custom-set-faces!
+ `((outline-1 outline-2 outline-3 outline-4 outline-5 outline-6)
+   :weight normal)
+ `((default region)
+   :background "red" :weight bold))
+
+(let ((red-bg-faces '(default region)))
+  (custom-set-faces!
+   `(,(cl-loop for i from 0 to 6 collect (intern (format "outline-%d" i)))
+     :weight normal)
+   `(,red-bg-faces
+     :background "red" :weight bold)))
+#+END_SRC
+
 * file-exists-p!
 #+BEGIN_SRC elisp
 (file-exists-p! "init.el" doom-emacs-dir)