diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index de3bd535a..0ade45a66 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -4,7 +4,7 @@ class ApplicationController < ActionController::Base
   include CurrentRequest, CurrentTimezone, SetPlatform
   include TurboFlash, ViewTransitions
   include Saas
-  include RoutingHeaders, WriterAffinity
+  include RoutingHeaders
 
   etag { "v1" }
   stale_when_importmap_changes
diff --git a/app/controllers/cards/readings_controller.rb b/app/controllers/cards/readings_controller.rb
index 887b5dd3d..95acc7511 100644
--- a/app/controllers/cards/readings_controller.rb
+++ b/app/controllers/cards/readings_controller.rb
@@ -1,8 +1,6 @@
 class Cards::ReadingsController < ApplicationController
   include CardScoped
 
-  skip_writer_affinity
-
   def create
     @notifications = @card.read_by(Current.user)
     record_board_access
diff --git a/app/controllers/concerns/writer_affinity.rb b/app/controllers/concerns/writer_affinity.rb
deleted file mode 100644
index da03e1a42..000000000
--- a/app/controllers/concerns/writer_affinity.rb
+++ /dev/null
@@ -1,14 +0,0 @@
-module WriterAffinity
-  extend ActiveSupport::Concern
-
-  class_methods do
-    def skip_writer_affinity(**)
-      before_action :set_writer_affinity_opt_out_header, **
-    end
-  end
-
-  private
-    def set_writer_affinity_opt_out_header
-      response.headers["X-Writer-Affinity"] = "false"
-    end
-end
diff --git a/config/initializers/multi_db.rb b/config/initializers/multi_db.rb
index b4d91085d..55c776c92 100644
--- a/config/initializers/multi_db.rb
+++ b/config/initializers/multi_db.rb
@@ -1,7 +1,7 @@
 require "deployment"
 
 Rails.application.configure do
-  config.active_record.database_selector = { delay: 1.second }
+  config.active_record.database_selector = { delay: 0.seconds }
   config.active_record.database_resolver = Deployment::DatabaseResolver
   config.active_record.database_resolver_context = ActiveRecord::Middleware::DatabaseSelector::Resolver::Session
 end
diff --git a/gems/fizzy-saas/lib/fizzy/saas/engine.rb b/gems/fizzy-saas/lib/fizzy/saas/engine.rb
index db24c8557..8db0f40bf 100644
--- a/gems/fizzy-saas/lib/fizzy/saas/engine.rb
+++ b/gems/fizzy-saas/lib/fizzy/saas/engine.rb
@@ -1,9 +1,19 @@
+require_relative "metrics"
+require_relative "transaction_pinning"
+
 module Fizzy
   module Saas
     class Engine < ::Rails::Engine
       # moved from config/initializers/queenbee.rb
       Queenbee.host_app = Fizzy
 
+      initializer "fizzy_saas.transaction_pinning" do |app|
+        app.config.middleware.insert_after(
+          ActiveRecord::Middleware::DatabaseSelector,
+          TransactionPinning::Middleware
+        )
+      end
+
       config.to_prepare do
         Queenbee::Subscription.short_names = Subscription::SHORT_NAMES
         Queenbee::ApiToken.token = Rails.application.credentials.dig(:queenbee_api_token)
diff --git a/gems/fizzy-saas/lib/fizzy/saas/metrics.rb b/gems/fizzy-saas/lib/fizzy/saas/metrics.rb
new file mode 100644
index 000000000..80a2bc194
--- /dev/null
+++ b/gems/fizzy-saas/lib/fizzy/saas/metrics.rb
@@ -0,0 +1,13 @@
+Yabeda.configure do
+  SHORT_HISTOGRAM_BUCKETS = [ 0.001, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5 ]
+
+  group :fizzy do
+    counter :replica_stale,
+      comment: "Number of requests served from a stale replica"
+
+    histogram :replica_wait,
+      unit: :seconds,
+      comment: "Time spent waiting for replica to catch up with transaction",
+      buckets: SHORT_HISTOGRAM_BUCKETS
+  end
+end
diff --git a/gems/fizzy-saas/lib/fizzy/saas/transaction_pinning.rb b/gems/fizzy-saas/lib/fizzy/saas/transaction_pinning.rb
new file mode 100644
index 000000000..ed3cf2060
--- /dev/null
+++ b/gems/fizzy-saas/lib/fizzy/saas/transaction_pinning.rb
@@ -0,0 +1,65 @@
+module TransactionPinning
+  class Middleware
+    SESSION_KEY = :last_txn
+    DEFAULT_MAX_WAIT = 0.25
+
+    def initialize(app)
+      @app = app
+      @timeout = Rails.application.config.x.transaction_pinning&.timeout&.to_f || DEFAULT_MAX_WAIT
+    end
+
+    def call(env)
+      request = ActionDispatch::Request.new(env)
+      replica_metrics = {}
+
+      if ApplicationRecord.current_role == :reading
+        wait_for_replica_catchup(request, replica_metrics)
+      end
+
+      status, headers, body = @app.call(env)
+      headers.merge!(replica_metrics.transform_values(&:to_s))
+
+      if ApplicationRecord.current_role == :writing
+        capture_transaction_id(request)
+      end
+
+      [ status, headers, body ]
+    end
+
+    private
+      def wait_for_replica_catchup(request, replica_metrics)
+        if last_txn = request.session[SESSION_KEY].presence
+          has_transaction = tracking_replica_wait_time(replica_metrics) do
+            replica_has_transaction(last_txn)
+          end
+
+          unless has_transaction
+            Yabeda.fizzy.replica_stale.increment
+            replica_metrics["X-Replica-Stale"] = true
+          end
+        end
+      end
+
+      def capture_transaction_id(request)
+        request.session[SESSION_KEY] = ApplicationRecord.connection.show_variable("global.gtid_executed")
+      end
+
+      def replica_has_transaction(txn)
+        sql = ApplicationRecord.sanitize_sql_array([ "SELECT WAIT_FOR_EXECUTED_GTID_SET(?, ?)", txn, @timeout ])
+        ApplicationRecord.connection.select_value(sql) == 0
+      rescue => e
+        Sentry.capture_exception(e, extra: { gtid: txn })
+        true # Treat as if we're up to date, since we don't know
+      end
+
+      def tracking_replica_wait_time(replica_metrics)
+        started_at = Time.current
+
+        Yabeda.fizzy.replica_wait.measure do
+          yield
+        end.tap do
+          replica_metrics["X-Replica-Wait"] = Time.current - started_at
+        end
+      end
+  end
+end
diff --git a/script/configure-lb-production.sh b/script/configure-lb-production.sh
index f961adb4a..7d7dfdbf4 100755
--- a/script/configure-lb-production.sh
+++ b/script/configure-lb-production.sh
@@ -10,7 +10,7 @@ ssh app@fizzy-lb-101.df-iad-int.37signals.com \
       --force \
       --tls \
       --host=app.fizzy.do \
-      --writer-affinity-timeout=1s \
+      --writer-affinity-timeout=0 \
       --tls-acme-cache-path=/certificates \
       --target=fizzy-app-101.df-iad-int.37signals.com \
       --target=fizzy-app-102.df-iad-int.37signals.com
@@ -24,7 +24,7 @@ ssh app@fizzy-lb-01.sc-chi-int.37signals.com \
       --force \
       --tls \
       --host=app.fizzy.do \
-      --writer-affinity-timeout=1s \
+      --writer-affinity-timeout=0 \
       --tls-acme-cache-path=/certificates \
       --target=fizzy-app-101.df-iad-int.37signals.com \
       --target=fizzy-app-102.df-iad-int.37signals.com \
@@ -40,7 +40,7 @@ ssh app@fizzy-lb-401.df-ams-int.37signals.com \
       --force \
       --tls \
       --host=app.fizzy.do \
-      --writer-affinity-timeout=1s \
+      --writer-affinity-timeout=0 \
       --tls-acme-cache-path=/certificates \
       --target=fizzy-app-101.df-iad-int.37signals.com \
       --target=fizzy-app-102.df-iad-int.37signals.com \
diff --git a/script/configure-lb-staging.sh b/script/configure-lb-staging.sh
index 789865d16..3e88cbcb1 100755
--- a/script/configure-lb-staging.sh
+++ b/script/configure-lb-staging.sh
@@ -10,7 +10,7 @@ ssh app@fizzy-staging-lb-01.sc-chi-int.37signals.com \
       --force \
       --tls \
       --host=fizzy.37signals-staging.com \
-      --writer-affinity-timeout=1s \
+      --writer-affinity-timeout=0 \
       --tls-acme-cache-path=/certificates \
       --target=fizzy-staging-app-101.df-iad-int.37signals.com \
       --target=fizzy-staging-app-102.df-iad-int.37signals.com \
@@ -25,7 +25,7 @@ ssh app@fizzy-staging-lb-101.df-iad-int.37signals.com \
       --force \
       --tls \
       --host=fizzy.37signals-staging.com \
-      --writer-affinity-timeout=1s \
+      --writer-affinity-timeout=0 \
       --tls-acme-cache-path=/certificates \
       --target=fizzy-staging-app-101.df-iad-int.37signals.com \
       --target=fizzy-staging-app-102.df-iad-int.37signals.com
@@ -38,7 +38,7 @@ ssh app@fizzy-staging-lb-401.df-ams-int.37signals.com \
       --force \
       --tls \
       --host=fizzy.37signals-staging.com \
-      --writer-affinity-timeout=1s \
+      --writer-affinity-timeout=0 \
       --tls-acme-cache-path=/certificates \
       --target=fizzy-staging-app-101.df-iad-int.37signals.com \
       --target=fizzy-staging-app-102.df-iad-int.37signals.com \
diff --git a/test/controllers/cards/readings_controller_test.rb b/test/controllers/cards/readings_controller_test.rb
index fc0e83c78..b7f7474c7 100644
--- a/test/controllers/cards/readings_controller_test.rb
+++ b/test/controllers/cards/readings_controller_test.rb
@@ -35,12 +35,6 @@ class Cards::ReadingsControllerTest < ActionDispatch::IntegrationTest
     assert_response :success
   end
 
-  test "create opts-out of writer affinity in the load balancer" do
-    post card_reading_path(cards(:logo)), as: :turbo_stream
-
-    assert_equal "false", response.headers["X-Writer-Affinity"]
-  end
-
   test "destroy" do
     freeze_time