diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 121272ca..93785f82 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -19,14 +19,14 @@ jobs:
         ports:
           - 6379:6379
       memcached:
-        image: memcached:1.6.9
+        image: memcached:1.6
         ports:
           - 11211:11211
         options: --health-cmd "timeout 5 bash -c 'cat < /dev/null > /dev/udp/127.0.0.1/11211'" --health-interval 10s --health-timeout 5s --health-retries 5
     strategy:
       fail-fast: false
       matrix:
-        ruby: ["3.4", "3.3", "3.2"]
+        ruby: ["4.0", "3.4", "3.3", "3.2"]
         rack: ["2.2.0", "3.1.0", "3.2.0"]
     env:
       RACK_VERSION: ${{ matrix.rack }}
diff --git a/docs/screenshots/rmp_01_toolbar.png b/docs/screenshots/rmp_01_toolbar.png
new file mode 100644
index 00000000..9f4fb8be
Binary files /dev/null and b/docs/screenshots/rmp_01_toolbar.png differ
diff --git a/docs/screenshots/rmp_02_expanded.png b/docs/screenshots/rmp_02_expanded.png
new file mode 100644
index 00000000..9f4fb8be
Binary files /dev/null and b/docs/screenshots/rmp_02_expanded.png differ
diff --git a/docs/screenshots/rmp_03_flamegraph.png b/docs/screenshots/rmp_03_flamegraph.png
new file mode 100644
index 00000000..0c9acf4a
Binary files /dev/null and b/docs/screenshots/rmp_03_flamegraph.png differ
diff --git a/lib/mini_profiler.rb b/lib/mini_profiler.rb
index 3eb012bc..736fc750 100644
--- a/lib/mini_profiler.rb
+++ b/lib/mini_profiler.rb
@@ -283,7 +283,50 @@ def call(env)
         env['HTTP_ACCEPT_ENCODING'] = 'identity' if config.suppress_encoding
 
         if matches_action?('flamegraph', env) || matches_action?('async-flamegraph', env) || env['HTTP_REFERER'] =~ /pp=async-flamegraph/
-          if defined?(StackProf) && StackProf.respond_to?(:run)
+          profiler_param = action_parameters(env)['flamegraph_profiler']
+          stackprof_available = defined?(StackProf) && StackProf.respond_to?(:run)
+          use_rperf = if profiler_param
+            profiler_param == 'rperf'
+          else
+            config.flamegraph_profiler == :rperf ||
+              (config.flamegraph_profiler == :auto &&
+               !stackprof_available &&
+               defined?(Rperf) && Rperf.respond_to?(:start))
+          end
+
+          if use_rperf
+            if defined?(Rperf) && Rperf.respond_to?(:start)
+              current.measure = false
+              match_data = action_parameters(env)['flamegraph_sample_rate']
+              frequency = if match_data && !match_data[1].to_f.zero?
+                match_data[1].to_f
+              else
+                config.flamegraph_sample_rate
+              end
+              frequency = frequency.to_i
+              frequency = 500 if frequency < 1
+
+              mode_match = action_parameters(env)['flamegraph_mode']
+              mode = if mode_match && [:cpu, :wall].include?(mode_match.to_sym)
+                mode_match.to_sym
+              else
+                config.flamegraph_mode == :object ? :wall : config.flamegraph_mode
+              end
+
+              Rperf.start(mode: mode, frequency: frequency)
+              status, headers, body = @app.call(env)
+              raw_data = Rperf.stop
+              flamegraph = rperf_to_speedscope(raw_data)
+            else
+              message = "Please install the rperf gem and require it: add gem 'rperf' to your Gemfile"
+              status, headers, body = @app.call(env)
+              body.close if body.respond_to? :close
+
+              return client_settings.handle_cookie(
+                text_result(message, status: status, headers: headers)
+              )
+            end
+          elsif stackprof_available
             # do not sully our profile with mini profiler timings
             current.measure = false
             match_data      = action_parameters(env)['flamegraph_sample_rate']
@@ -619,6 +662,40 @@ def cache_control_value
       86400
     end
 
+    def rperf_to_speedscope(data)
+      frame_index = {}
+      frames      = []
+      samples     = []
+      weights     = []
+
+      (data[:samples] || []).each do |stack_frames, weight_ns, _thread|
+        sample_indices = stack_frames.map do |file, name|
+          key = "#{file}\0#{name}"
+          unless frame_index.key?(key)
+            frame_index[key] = frames.size
+            frames << { "name" => name.to_s, "file" => file.to_s }
+          end
+          frame_index[key]
+        end
+        samples << sample_indices
+        weights << weight_ns.to_i
+      end
+
+      {
+        "$schema" => "https://www.speedscope.app/file-format-schema.json",
+        "profiles" => [{
+          "type" => "sampled",
+          "name" => "rperf #{data[:mode]}",
+          "unit" => "nanoseconds",
+          "startValue" => 0,
+          "endValue" => (data[:duration_ns] || 0).to_i,
+          "samples" => samples,
+          "weights" => weights,
+        }],
+        "shared" => { "frames" => frames },
+      }
+    end
+
     private
 
     def rails_route_from_path(path, method)
diff --git a/lib/mini_profiler/config.rb b/lib/mini_profiler/config.rb
index 737399a0..2014fa81 100644
--- a/lib/mini_profiler/config.rb
+++ b/lib/mini_profiler/config.rb
@@ -31,6 +31,7 @@ def self.default
           @flamegraph_sample_rate = 0.5
           @flamegraph_mode = :wall
           @flamegraph_ignore_gc = false
+          @flamegraph_profiler = :auto
           @storage_failure = Proc.new do |exception|
             if @logger
               @logger.warn("MiniProfiler storage failure: #{exception.message}")
@@ -77,7 +78,7 @@ def self.default
         :storage_options, :user_provider, :enable_advanced_debugging_tools,
         :skip_sql_param_names, :suppress_encoding, :max_sql_param_length,
         :content_security_policy_nonce, :enable_hotwire_turbo_drive_support,
-        :flamegraph_mode, :flamegraph_ignore_gc, :profile_parameter
+        :flamegraph_mode, :flamegraph_ignore_gc, :flamegraph_profiler, :profile_parameter
 
       # ui accessors
       attr_accessor :collapse_results, :max_traces_to_show, :position,
diff --git a/lib/mini_profiler/storage/memcache_store.rb b/lib/mini_profiler/storage/memcache_store.rb
index 5a143049..347140e0 100644
--- a/lib/mini_profiler/storage/memcache_store.rb
+++ b/lib/mini_profiler/storage/memcache_store.rb
@@ -67,7 +67,7 @@ def get_unviewed_ids(user)
       end
 
       def flush_tokens
-        @client.set("#{@prefix}-tokens", nil)
+        @client.delete("#{@prefix}-tokens")
       end
 
       def allowed_tokens
diff --git a/lib/mini_profiler/views.rb b/lib/mini_profiler/views.rb
index 87566881..2e4bdcc7 100644
--- a/lib/mini_profiler/views.rb
+++ b/lib/mini_profiler/views.rb
@@ -167,6 +167,8 @@ def help(client_settings, env)
                 #{make_link "flamegraph&flamegraph_sample_rate=1", env}: creates a flamegraph with the specified sample rate (in ms). Overrides value set in config
                 #{make_link "flamegraph&flamegraph_mode=cpu", env}: creates a flamegraph with the specified mode (one of cpu, wall, object, or custom). Overrides value set in config
                 #{make_link "flamegraph&flamegraph_ignore_gc=true", env}: ignore garbage collection frames in flamegraphs. Overrides value set in config
+                #{make_link "flamegraph&flamegraph_profiler=rperf", env} : flamegraph using rperf (requires the rperf gem, Ruby >= 3.4).
+                #{make_link "flamegraph&flamegraph_profiler=rperf&flamegraph_mode=wall", env} : rperf wall-mode flamegraph (shows GVL/GC time attribution).
                 #{make_link "flamegraph_embed", env} : a graph representing sampled activity (requires the stackprof gem), embedded resources for use on an intranet.
                 #{make_link "trace-exceptions", env} : will return all the spots where your application raises exceptions
                 #{make_link "analyze-memory", env} : will perform basic memory analysis of heap
diff --git a/lib/mini_profiler_rails/railtie.rb b/lib/mini_profiler_rails/railtie.rb
index b3f2c8cb..d8f4bac7 100644
--- a/lib/mini_profiler_rails/railtie.rb
+++ b/lib/mini_profiler_rails/railtie.rb
@@ -34,7 +34,7 @@ def self.initialize!(app)
       c.skip_paths << wp_assets_path if wp_assets_path
     end
 
-    unless Rails.env.development? || Rails.env.test?
+    unless Rails.env.local?
       c.authorization_mode = :allow_authorized
     end
 
@@ -55,7 +55,7 @@ def self.initialize!(app)
     # Quiet the SQL stack traces
     c.backtrace_remove = Rails.root.to_s + "/"
     c.backtrace_includes =  [/^\/?(app|config|lib|test)/]
-    c.skip_schema_queries = (Rails.env.development? || Rails.env.test?)
+    c.skip_schema_queries = (Rails.env.local?)
 
     # Install the Middleware
     app.middleware.insert(0, Rack::MiniProfiler)
diff --git a/spec/lib/rperf_flamegraph_spec.rb b/spec/lib/rperf_flamegraph_spec.rb
new file mode 100644
index 00000000..c690598b
--- /dev/null
+++ b/spec/lib/rperf_flamegraph_spec.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
+RSpec.describe "rperf flamegraph integration" do # rubocop:disable RSpec/DescribeClass
+  before do
+    skip "rperf not available" unless defined?(Rperf) && Rperf.respond_to?(:start)
+  end
+
+  let(:profiler) { Rack::MiniProfiler.new(app) }
+  let(:app) { lambda { |_env| [200, {}, ["ok"]] } }
+
+  before do
+    Rack::MiniProfiler.reset_config
+    Rack::MiniProfiler.config.storage = Rack::MiniProfiler::MemoryStore
+    Rack::MiniProfiler.config.flamegraph_profiler = :rperf
+  end
+
+  it "returns error when rperf is not installed" do
+    hide_const("Rperf")
+    response = profiler.call({ "PATH_INFO" => "/", "QUERY_STRING" => "pp=flamegraph" })
+    expect(response[2]).to include("Please install the rperf gem")
+  end
+
+  it "generates valid speedscope JSON for flamegraph" do
+    require "rperf"
+    Rack::MiniProfiler.config.flamegraph_profiler = :rperf
+    response = profiler.call({ "PATH_INFO" => "/", "QUERY_STRING" => "pp=flamegraph" })
+    expect(response[0]).to eq(200)
+    body = response[2].join
+    expect(body).to include("speedscope")
+  end
+end