diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1495,6 +1495,7 @@
     'PhabricatorCacheSpec' => 'applications/cache/spec/PhabricatorCacheSpec.php',
     'PhabricatorCacheTTLGarbageCollector' => 'applications/cache/garbagecollector/PhabricatorCacheTTLGarbageCollector.php',
     'PhabricatorCaches' => 'applications/cache/PhabricatorCaches.php',
+    'PhabricatorCachesTestCase' => 'applications/cache/__tests__/PhabricatorCachesTestCase.php',
     'PhabricatorCalendarApplication' => 'applications/calendar/application/PhabricatorCalendarApplication.php',
     'PhabricatorCalendarController' => 'applications/calendar/controller/PhabricatorCalendarController.php',
     'PhabricatorCalendarDAO' => 'applications/calendar/storage/PhabricatorCalendarDAO.php',
@@ -4852,6 +4853,7 @@
     'PhabricatorCacheSetupCheck' => 'PhabricatorSetupCheck',
     'PhabricatorCacheSpec' => 'Phobject',
     'PhabricatorCacheTTLGarbageCollector' => 'PhabricatorGarbageCollector',
+    'PhabricatorCachesTestCase' => 'PhabricatorTestCase',
     'PhabricatorCalendarApplication' => 'PhabricatorApplication',
     'PhabricatorCalendarController' => 'PhabricatorController',
     'PhabricatorCalendarDAO' => 'PhabricatorLiskDAO',
diff --git a/src/applications/cache/PhabricatorCaches.php b/src/applications/cache/PhabricatorCaches.php
--- a/src/applications/cache/PhabricatorCaches.php
+++ b/src/applications/cache/PhabricatorCaches.php
@@ -1,12 +1,16 @@
 <?php
 
 /**
+ *
+ * @task request    Request Cache
  * @task immutable  Immutable Cache
  * @task setup      Setup Cache
  * @task compress   Compression
  */
 final class PhabricatorCaches {
 
+  private static $requestCache;
+
   public static function getNamespace() {
     return PhabricatorEnv::getEnvConfig('phabricator.cache-namespace');
   }
@@ -18,8 +22,39 @@
       ->setCaches($caches);
   }
 
+/* -(  Request Cache  )------------------------------------------------------ */
+
+
+  /**
+   * Get a request cache stack.
+   *
+   * This cache stack is destroyed after each logical request. In particular,
+   * it is destroyed periodically by the daemons, while `static` caches are
+   * not.
+   *
+   * @return PhutilKeyValueCacheStack Request cache stack.
+   */
+  public static function getRequestCache() {
+    if (!self::$requestCache) {
+      self::$requestCache = new PhutilInRequestKeyValueCache();
+    }
+    return self::$requestCache;
+  }
+
+
+  /**
+   * Destroy the request cache.
+   *
+   * This is called at the beginning of each logical request.
+   *
+   * @return void
+   */
+  public static function destroyRequestCache() {
+    self::$requestCache = null;
+  }
+
 
-/* -(  Local Cache  )-------------------------------------------------------- */
+/* -(  Immutable Cache  )---------------------------------------------------- */
 
 
   /**
diff --git a/src/applications/cache/__tests__/PhabricatorCachesTestCase.php b/src/applications/cache/__tests__/PhabricatorCachesTestCase.php
new file mode 100644
--- /dev/null
+++ b/src/applications/cache/__tests__/PhabricatorCachesTestCase.php
@@ -0,0 +1,41 @@
+<?php
+
+final class PhabricatorCachesTestCase
+  extends PhabricatorTestCase {
+
+  public function testRequestCache() {
+    $cache = PhabricatorCaches::getRequestCache();
+
+    $test_key = 'unit.'.Filesystem::readRandomCharacters(8);
+
+    $default_value = pht('Default');
+    $new_value = pht('New Value');
+
+    $this->assertEqual(
+      $default_value,
+      $cache->getKey($test_key, $default_value));
+
+    // Set a key, verify it persists.
+    $cache = PhabricatorCaches::getRequestCache();
+    $cache->setKey($test_key, $new_value);
+    $this->assertEqual(
+      $new_value,
+      $cache->getKey($test_key, $default_value));
+
+    // Refetch the cache, verify it's really a cache.
+    $cache = PhabricatorCaches::getRequestCache();
+    $this->assertEqual(
+      $new_value,
+      $cache->getKey($test_key, $default_value));
+
+    // Destroy the cache.
+    PhabricatorCaches::destroyRequestCache();
+
+    // Now, the value should be missing again.
+    $cache = PhabricatorCaches::getRequestCache();
+    $this->assertEqual(
+      $default_value,
+      $cache->getKey($test_key, $default_value));
+  }
+
+}
diff --git a/src/applications/fact/daemon/PhabricatorFactDaemon.php b/src/applications/fact/daemon/PhabricatorFactDaemon.php
--- a/src/applications/fact/daemon/PhabricatorFactDaemon.php
+++ b/src/applications/fact/daemon/PhabricatorFactDaemon.php
@@ -9,6 +9,8 @@
   protected function run() {
     $this->setEngines(PhabricatorFactEngine::loadAllEngines());
     while (!$this->shouldExit()) {
+      PhabricatorCaches::destroyRequestCache();
+
       $iterators = $this->getAllApplicationIterators();
       foreach ($iterators as $iterator_name => $iterator) {
         $this->processIteratorWithCursor($iterator_name, $iterator);
diff --git a/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php b/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php
--- a/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php
+++ b/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php
@@ -73,6 +73,7 @@
     $queue = array();
 
     while (!$this->shouldExit()) {
+      PhabricatorCaches::destroyRequestCache();
       $pullable = $this->loadPullableRepositories($include, $exclude);
 
       // If any repositories have the NEEDS_UPDATE flag set, pull them
diff --git a/src/infrastructure/daemon/bot/PhabricatorBot.php b/src/infrastructure/daemon/bot/PhabricatorBot.php
--- a/src/infrastructure/daemon/bot/PhabricatorBot.php
+++ b/src/infrastructure/daemon/bot/PhabricatorBot.php
@@ -106,6 +106,8 @@
 
   private function runLoop() {
     do {
+      PhabricatorCaches::destroyRequestCache();
+
       $this->stillWorking();
 
       $messages = $this->protocolAdapter->getNextMessages($this->pollFrequency);
diff --git a/src/infrastructure/daemon/workers/PhabricatorTaskmasterDaemon.php b/src/infrastructure/daemon/workers/PhabricatorTaskmasterDaemon.php
--- a/src/infrastructure/daemon/workers/PhabricatorTaskmasterDaemon.php
+++ b/src/infrastructure/daemon/workers/PhabricatorTaskmasterDaemon.php
@@ -4,6 +4,8 @@
 
   protected function run() {
     do {
+      PhabricatorCaches::destroyRequestCache();
+
       $tasks = id(new PhabricatorWorkerLeaseQuery())
         ->setLimit(1)
         ->execute();
diff --git a/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php b/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php
--- a/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php
+++ b/src/infrastructure/daemon/workers/PhabricatorTriggerDaemon.php
@@ -65,6 +65,8 @@
     $this->nextCollection = PhabricatorTime::getNow();
 
     do {
+      PhabricatorCaches::destroyRequestCache();
+
       $lock = PhabricatorGlobalLock::newLock('trigger');
 
       try {
diff --git a/webroot/index.php b/webroot/index.php
--- a/webroot/index.php
+++ b/webroot/index.php
@@ -13,6 +13,8 @@
 
 try {
   PhabricatorStartup::loadCoreLibraries();
+  PhabricatorCaches::destroyRequestCache();
+
   $sink = new AphrontPHPHTTPSink();
 
   try {