diff --git a/sanitize.gemspec b/sanitize.gemspec
index 27d8aa8..4f28b23 100644
--- a/sanitize.gemspec
+++ b/sanitize.gemspec
@@ -16,6 +16,11 @@ Gem::Specification.new do |s|
   s.required_ruby_version = Gem::Requirement.new('>= 2.5.0')
   s.required_rubygems_version = Gem::Requirement.new('>= 1.2.0')
 
+  s.metadata = {
+    "changelog_uri"     => "https://github.com/rgrove/sanitize/blob/main/HISTORY.md",
+    "documentation_uri" => "https://rubydoc.info/github/rgrove/sanitize"
+  }
+
   # Runtime dependencies.
   s.add_dependency('crass', '~> 1.0.2')
   s.add_dependency('nokogiri', '>= 1.12.0')