diff --git a/pkgs/development/ruby-modules/with-packages/Gemfile b/pkgs/development/ruby-modules/with-packages/Gemfile
index dda0f69c35cc..bfb52fe72e7a 100644
--- a/pkgs/development/ruby-modules/with-packages/Gemfile
+++ b/pkgs/development/ruby-modules/with-packages/Gemfile
@@ -74,6 +74,7 @@ source 'https://rubygems.org' do
   gem 'jekyll'
   gem 'jmespath'
   gem 'jwt'
+  gem 'kramdown-rfc2629'
   gem 'libv8'
   gem 'libxml-ruby'
   gem 'magic'
diff --git a/pkgs/tools/text/kramdown-rfc2629/Gemfile b/pkgs/tools/text/kramdown-rfc2629/Gemfile
deleted file mode 100644
index 9b3347860b65..000000000000
--- a/pkgs/tools/text/kramdown-rfc2629/Gemfile
+++ /dev/null
@@ -1,2 +0,0 @@
-source 'https://rubygems.org'
-gem 'kramdown-rfc2629'
diff --git a/pkgs/tools/text/kramdown-rfc2629/Gemfile.lock b/pkgs/tools/text/kramdown-rfc2629/Gemfile.lock
deleted file mode 100644
index feab5cddf995..000000000000
--- a/pkgs/tools/text/kramdown-rfc2629/Gemfile.lock
+++ /dev/null
@@ -1,19 +0,0 @@
-GEM
-  remote: https://rubygems.org/
-  specs:
-    certified (1.0.0)
-    json_pure (2.5.1)
-    kramdown (1.17.0)
-    kramdown-rfc2629 (1.3.37)
-      certified (~> 1.0)
-      json_pure (~> 2.0)
-      kramdown (~> 1.17.0)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  kramdown-rfc2629
-
-BUNDLED WITH
-   2.1.4
diff --git a/pkgs/tools/text/kramdown-rfc2629/default.nix b/pkgs/tools/text/kramdown-rfc2629/default.nix
deleted file mode 100644
index 945c676ca18d..000000000000
--- a/pkgs/tools/text/kramdown-rfc2629/default.nix
+++ /dev/null
@@ -1,18 +0,0 @@
-{ lib, bundlerApp }:
-
-# Not in the default ../../../development/ruby-modules/with-packages/Gemfile
-# because of version clash on the "kramdown" dependency.
-bundlerApp rec {
-  pname = "kramdown-rfc2629";
-  gemdir = ./.;
-  exes = [ "kramdown-rfc2629" ];
-
-  meta = with lib; {
-    description = "A markdown parser with multiple backends";
-    homepage    = "https://github.com/cabo/kramdown-rfc2629";
-    license     = with licenses; mit;
-    maintainers = with maintainers; [
-      vcunat # not really, but I expect to use it occasionally around IETF
-    ];
-  };
-}
diff --git a/pkgs/tools/text/kramdown-rfc2629/gemset.nix b/pkgs/tools/text/kramdown-rfc2629/gemset.nix
deleted file mode 100644
index f0b6c39a3599..000000000000
--- a/pkgs/tools/text/kramdown-rfc2629/gemset.nix
+++ /dev/null
@@ -1,43 +0,0 @@
-{
-  certified = {
-    groups = ["default"];
-    platforms = [];
-    source = {
-      remotes = ["https://rubygems.org"];
-      sha256 = "1706p6p0a8adyvd943af2a3093xakvislgffw3v9dvp7j07dyk5a";
-      type = "gem";
-    };
-    version = "1.0.0";
-  };
-  json_pure = {
-    groups = ["default"];
-    platforms = [];
-    source = {
-      remotes = ["https://rubygems.org"];
-      sha256 = "030hmc268wchqsccbjk41hvbyg99krpa72i3q0y3wwqzfh8hi736";
-      type = "gem";
-    };
-    version = "2.5.1";
-  };
-  kramdown = {
-    groups = ["default"];
-    platforms = [];
-    source = {
-      remotes = ["https://rubygems.org"];
-      sha256 = "1n1c4jmrh5ig8iv1rw81s4mw4xsp4v97hvf8zkigv4hn5h542qjq";
-      type = "gem";
-    };
-    version = "1.17.0";
-  };
-  kramdown-rfc2629 = {
-    dependencies = ["certified" "json_pure" "kramdown"];
-    groups = ["default"];
-    platforms = [];
-    source = {
-      remotes = ["https://rubygems.org"];
-      sha256 = "16m08q5bgib3i54bb9p3inrxb1xksiybs9zj1rnncq492gcqqv4j";
-      type = "gem";
-    };
-    version = "1.3.37";
-  };
-}
diff --git a/pkgs/top-level/aliases.nix b/pkgs/top-level/aliases.nix
index 12704a3c0fcb..d05c81dcaa9f 100644
--- a/pkgs/top-level/aliases.nix
+++ b/pkgs/top-level/aliases.nix
@@ -341,6 +341,7 @@ mapAliases ({
   krename-qt5 = krename; # added 2017-02-18
   kerberos = libkrb5; # moved from top-level 2021-03-14
   keymon = throw "keymon has been removed from nixpkgs, as it's abandoned and archived."; # 2019-12-10
+  kramdown-rfc2629 = rubyPackages.kramdown-rfc2629; # added 2021-03-23
   kvm = qemu_kvm; # added 2018-04-25
   latinmodern-math = lmmath;
   letsencrypt = certbot; # added 2016-05-16
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 5efe5b519ebe..9cbea851c521 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -2665,8 +2665,6 @@ in
 
   klaus = with python3Packages; toPythonApplication klaus;
 
-  kramdown-rfc2629 = callPackage ../tools/text/kramdown-rfc2629 { };
-
   klipper = callPackage ../servers/klipper { };
 
   klog = qt5.callPackage ../applications/radio/klog { };
diff --git a/pkgs/top-level/ruby-packages.nix b/pkgs/top-level/ruby-packages.nix
index 13e91d5b0f69..b25f854bdd06 100644
--- a/pkgs/top-level/ruby-packages.nix
+++ b/pkgs/top-level/ruby-packages.nix
@@ -235,6 +235,16 @@
     };
     version = "2.1.532";
   };
+  certified = {
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "1706p6p0a8adyvd943af2a3093xakvislgffw3v9dvp7j07dyk5a";
+      type = "gem";
+    };
+    version = "1.0.0";
+  };
   CFPropertyList = {
     groups = ["default"];
     platforms = [];
@@ -1222,6 +1232,16 @@
     };
     version = "2.5.1";
   };
+  json_pure = {
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "030hmc268wchqsccbjk41hvbyg99krpa72i3q0y3wwqzfh8hi736";
+      type = "gem";
+    };
+    version = "2.5.1";
+  };
   jwt = {
     groups = ["default"];
     platforms = [];
@@ -1254,6 +1274,17 @@
     };
     version = "1.1.0";
   };
+  kramdown-rfc2629 = {
+    dependencies = ["certified" "json_pure" "kramdown"];
+    groups = ["default"];
+    platforms = [];
+    source = {
+      remotes = ["https://rubygems.org"];
+      sha256 = "1p1iviq8q9za2hg0vqyrarrc3mqfskgp7spxp37xj0kl3g89vswq";
+      type = "gem";
+    };
+    version = "1.4.1";
+  };
   libv8 = {
     groups = ["default"];
     platforms = [];