diff --git a/lib/app_profiler.rb b/lib/app_profiler.rb
index ff79bdb..8fa484d 100644
--- a/lib/app_profiler.rb
+++ b/lib/app_profiler.rb
@@ -30,6 +30,7 @@ module Storage
   module Viewer
     autoload :BaseViewer, "app_profiler/viewer/base_viewer"
     autoload :SpeedscopeViewer, "app_profiler/viewer/speedscope_viewer"
+    autoload :FirefoxViewer, "app_profiler/viewer/firefox_viewer"
     autoload :BaseMiddleware, "app_profiler/viewer/base_middleware"
     autoload :SpeedscopeRemoteViewer, "app_profiler/viewer/speedscope_remote_viewer"
     autoload :FirefoxRemoteViewer, "app_profiler/viewer/firefox_remote_viewer"
@@ -125,7 +126,7 @@ def stackprof_viewer
     end
 
     def vernier_viewer
-      @@vernier_viewer ||= Viewer::FirefoxRemoteViewer # rubocop:disable Style/ClassVars
+      @@vernier_viewer ||= Viewer::FirefoxViewer # rubocop:disable Style/ClassVars
     end
 
     def profile_sampler_enabled=(value)
diff --git a/lib/app_profiler/exec.rb b/lib/app_profiler/exec.rb
new file mode 100644
index 0000000..9daf340
--- /dev/null
+++ b/lib/app_profiler/exec.rb
@@ -0,0 +1,35 @@
+module AppProfiler
+  module Exec # :nodoc:
+    protected
+
+    def valid_commands
+      raise NotImplementedError
+    end
+
+    def ensure_command_valid(command)
+      unless valid_command?(command)
+        raise YarnError, "Illegal command: #{command.join(" ")}."
+      end
+    end
+
+    def valid_command?(command)
+      valid_commands.any? do |valid_command|
+        next unless valid_command.size == command.size
+
+        valid_command.zip(command).all? do |valid_part, part|
+          part.match?(valid_part)
+        end
+      end
+    end
+
+    def exec(*command, silent: false, environment: {})
+      ensure_command_valid(command)
+
+      if silent
+        system(environment, *command, out: File::NULL).tap { |return_code| yield unless return_code }
+      else
+        system(environment, *command).tap { |return_code| yield unless return_code }
+      end
+    end
+  end
+end
diff --git a/lib/app_profiler/viewer/firefox_viewer.rb b/lib/app_profiler/viewer/firefox_viewer.rb
new file mode 100644
index 0000000..d3c023d
--- /dev/null
+++ b/lib/app_profiler/viewer/firefox_viewer.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require "app_profiler/exec"
+
+module AppProfiler
+  module Viewer
+    class FirefoxViewer < BaseViewer
+      include Exec
+
+      CHILD_PIDS = []
+
+      at_exit { sleep(1) until CHILD_PIDS.none? }
+
+      trap("INT") do
+        CHILD_PIDS.delete_if { |pid| Process.kill("INT", pid) }
+        sleep(0.5) # Wait for webrick logs
+      end
+
+      class ProfileViewerError < StandardError; end
+
+      VALID_COMMANDS = [
+        ["which", "profile-viewer"],
+        ["gem", "install", "profile-viewer"],
+        ["profile-viewer", /.*\.json/],
+      ]
+      private_constant(:VALID_COMMANDS)
+
+      class << self
+        def view(profile, params = {})
+          new(profile).view(**params)
+        end
+      end
+
+      def valid_commands
+        VALID_COMMANDS
+      end
+
+      def initialize(profile)
+        super()
+        @profile = profile
+      end
+
+      def view(_params = {})
+        profile_viewer(@profile.file.to_s)
+      end
+
+      private
+
+      def setup_profile_viewer
+        exec("which", "profile-viewer", silent: true) do
+          gem_install("profile_viewer")
+        end
+        @profile_viewer_initialized = true
+      end
+
+      def profile_viewer_setup
+        @profile_viewer_initialized || false
+      end
+
+      def gem_install(gem)
+        exec("gem", "install", gem) do
+          raise ProfileViewerError, "Failed to run gem install #{gem}."
+        end
+      end
+
+      def profile_viewer(path)
+        setup_profile_viewer unless profile_viewer_setup
+
+        CHILD_PIDS << fork do
+          Bundler.with_unbundled_env do
+            exec("profile-viewer", path) { AppProfiler.logger.info("Exiting")  }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/app_profiler/yarn/command.rb b/lib/app_profiler/yarn/command.rb
index 2002758..f0c989b 100644
--- a/lib/app_profiler/yarn/command.rb
+++ b/lib/app_profiler/yarn/command.rb
@@ -1,8 +1,12 @@
 # frozen_string_literal: true
 
+require "app_profiler/exec"
+
 module AppProfiler
   module Yarn
     module Command
+      include Exec
+
       class YarnError < StandardError; end
 
       VALID_COMMANDS = [
@@ -17,6 +21,10 @@ class YarnError < StandardError; end
 
       private_constant(:VALID_COMMANDS)
 
+      def valid_commands
+        VALID_COMMANDS
+      end
+
       def yarn(command, *options)
         setup_yarn unless yarn_setup
 
@@ -41,22 +49,6 @@ def yarn_setup=(state)
 
       private
 
-      def ensure_command_valid(command)
-        unless valid_command?(command)
-          raise YarnError, "Illegal command: #{command.join(" ")}."
-        end
-      end
-
-      def valid_command?(command)
-        VALID_COMMANDS.any? do |valid_command|
-          next unless valid_command.size == command.size
-
-          valid_command.zip(command).all? do |valid_part, part|
-            part.match?(valid_part)
-          end
-        end
-      end
-
       def ensure_yarn_installed
         exec("which", "yarn", silent: true) do
           raise(
@@ -73,16 +65,6 @@ def ensure_yarn_installed
       def package_json_exists?
         AppProfiler.root.join("package.json").exist?
       end
-
-      def exec(*command, silent: false)
-        ensure_command_valid(command)
-
-        if silent
-          system(*command, out: File::NULL).tap { |return_code| yield unless return_code }
-        else
-          system(*command).tap { |return_code| yield unless return_code }
-        end
-      end
     end
   end
 end