diff --git a/src/applications/files/config/PhabricatorFilesConfigOptions.php b/src/applications/files/config/PhabricatorFilesConfigOptions.php
--- a/src/applications/files/config/PhabricatorFilesConfigOptions.php
+++ b/src/applications/files/config/PhabricatorFilesConfigOptions.php
@@ -134,6 +134,19 @@
             "Set this to a valid Amazon S3 bucket to store files there. You ".
             "must also configure S3 access keys in the 'Amazon Web Services' ".
             "group.")),
+     $this->newOption('storage.enable-public-uri', 'bool', false)
+        ->setSummary(pht('Configure usage of Amazon S3 public URI.'))
+        ->setDescription(
+          pht(
+            "Change this to allow certain applications to return file URLs ".
+            "that directly point to files stored on S3.  This allows you ".
+            "to offload requests directly to Amazon and reduce load on ".
+            "the Phabricator server, at the cost of configuring Amazon S3 ".
+            "for public access.\n\n".
+            "NOTE: This currently only affects files which reside on the ".
+            "Amazon S3 storage engine.\n\n".
+            "NOTE: Currently Phragment's Conduit APIs are the only ".
+            "area that uses this functionality.")),
      $this->newOption(
        'storage.engine-selector',
        'class',
diff --git a/src/applications/files/engine/PhabricatorFileStorageEngine.php b/src/applications/files/engine/PhabricatorFileStorageEngine.php
--- a/src/applications/files/engine/PhabricatorFileStorageEngine.php
+++ b/src/applications/files/engine/PhabricatorFileStorageEngine.php
@@ -81,6 +81,25 @@
 
 
   /**
+   * Retrieve an absolute URI to which a download can be performed.  This
+   * can be used to direct downloads to Amazon S3 for non-user
+   * applications (such as Conduit APIs).
+   *
+   * This URL should not be provided to end users, as the underlying storage
+   * engine will most likely not provide the correct semantics for
+   * browser-based downloads.
+   *
+   * Return null to indicate that no public URI is available.
+   *
+   * @param   string  The handle returned from @{method:writeFile} when the
+   *                  file was written.
+   * @return  string  An absolute URI from which a download can be performed.
+   * @task file
+   */
+  abstract public function retrieveFileURI($handle);
+
+
+  /**
    * Delete the data for a file previously written by @{method:writeFile}.
    *
    * @param   string  The handle returned from @{method:writeFile} when the
diff --git a/src/applications/files/engine/PhabricatorLocalDiskFileStorageEngine.php b/src/applications/files/engine/PhabricatorLocalDiskFileStorageEngine.php
--- a/src/applications/files/engine/PhabricatorLocalDiskFileStorageEngine.php
+++ b/src/applications/files/engine/PhabricatorLocalDiskFileStorageEngine.php
@@ -66,6 +66,15 @@
 
 
   /**
+   * Return null because there are no direct download URI.
+   * @task impl
+   */
+  public function retrieveFileURI($handle) {
+    return null;
+  }
+
+
+  /**
    * Deletes the file from local disk, if it exists.
    * @task impl
    */
diff --git a/src/applications/files/engine/PhabricatorMySQLFileStorageEngine.php b/src/applications/files/engine/PhabricatorMySQLFileStorageEngine.php
--- a/src/applications/files/engine/PhabricatorMySQLFileStorageEngine.php
+++ b/src/applications/files/engine/PhabricatorMySQLFileStorageEngine.php
@@ -51,6 +51,15 @@
 
 
   /**
+   * Return null because there are no direct download URI.
+   * @task impl
+   */
+  public function retrieveFileURI($handle) {
+    return null;
+  }
+
+
+  /**
    * Delete a blob from MySQL.
    * @task impl
    */
diff --git a/src/applications/files/engine/PhabricatorS3FileStorageEngine.php b/src/applications/files/engine/PhabricatorS3FileStorageEngine.php
--- a/src/applications/files/engine/PhabricatorS3FileStorageEngine.php
+++ b/src/applications/files/engine/PhabricatorS3FileStorageEngine.php
@@ -69,6 +69,19 @@
 
 
   /**
+   * Return absolute public URI for redirected download.
+   * @task impl
+   */
+  public function retrieveFileURI($handle) {
+    $base_uri = 'https://'.$this->getBucketName().'.s3.amazonaws.com/';
+    if ($base_uri === null) {
+      return null;
+    }
+    return $base_uri.$handle;
+  }
+
+
+  /**
    * Delete a blob from Amazon S3.
    */
   public function deleteFile($handle) {
diff --git a/src/applications/files/engine/PhabricatorTestStorageEngine.php b/src/applications/files/engine/PhabricatorTestStorageEngine.php
--- a/src/applications/files/engine/PhabricatorTestStorageEngine.php
+++ b/src/applications/files/engine/PhabricatorTestStorageEngine.php
@@ -26,6 +26,10 @@
     throw new Exception("No such file with handle '{$handle}'!");
   }
 
+  public function retrieveFileURI($handle) {
+    return null;
+  }
+
   public function deleteFile($handle) {
     AphrontWriteGuard::willWrite();
     unset(self::$storage[$handle]);
diff --git a/src/applications/files/storage/PhabricatorFile.php b/src/applications/files/storage/PhabricatorFile.php
--- a/src/applications/files/storage/PhabricatorFile.php
+++ b/src/applications/files/storage/PhabricatorFile.php
@@ -506,6 +506,22 @@
     return PhabricatorEnv::getCDNURI($path);
   }
 
+  public function getMostDirectURI() {
+    if (PhabricatorEnv::getEnvConfig('storage.enable-public-uri')) {
+      // Redirect to the public URI if it's present.  This means Conduit
+      // methods such as phragment.getstate will return URLs directly
+      // pointing to Amazon for downloading files.
+      $engine = $this->instantiateStorageEngine();
+      $uri = $engine->retrieveFileURI($this->getStorageHandle());
+      if ($uri === null) {
+        return $this->getDownloadURI();
+      }
+      return $uri;
+    } else {
+      return $this->getDownloadURI();
+    }
+  }
+
   public function getInfoURI() {
     return '/file/info/'.$this->getPHID().'/';
   }
diff --git a/src/applications/phragment/conduit/PhragmentQueryFragmentsConduitAPIMethod.php b/src/applications/phragment/conduit/PhragmentQueryFragmentsConduitAPIMethod.php
--- a/src/applications/phragment/conduit/PhragmentQueryFragmentsConduitAPIMethod.php
+++ b/src/applications/phragment/conduit/PhragmentQueryFragmentsConduitAPIMethod.php
@@ -74,7 +74,7 @@
           'path' => $cpath,
           'hash' => $file->getContentHash(),
           'version' => $child->getLatestVersion()->getSequence(),
-          'uri' => $file->getViewURI());
+          'uri' => $file->getMostDirectURI());
       }
       $results[$path] = $result;
     }