diff --git a/docs/api.md b/docs/api.md
index 6a7e5e3180..d6cb1505f1 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -798,6 +798,8 @@ Gets the full HTML contents of the page, including the doctype.
 
 - returns: <[Coverage]>
 
+> **NOTE** Code coverage is currently only supported in Chromium headless.
+
 #### page.dblclick(selector[, options])
 - `selector` <[string]> A selector to search for element to double click. If there are multiple elements satisfying the selector, the first will be double clicked.
 - `options` <[Object]>