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
@@ -2983,6 +2983,7 @@
     'PhabricatorDraftEngine' => 'applications/transactions/draft/PhabricatorDraftEngine.php',
     'PhabricatorDraftInterface' => 'applications/transactions/draft/PhabricatorDraftInterface.php',
     'PhabricatorDrydockApplication' => 'applications/drydock/application/PhabricatorDrydockApplication.php',
+    'PhabricatorDuoFuture' => 'applications/auth/future/PhabricatorDuoFuture.php',
     'PhabricatorEdgeChangeRecord' => 'infrastructure/edges/util/PhabricatorEdgeChangeRecord.php',
     'PhabricatorEdgeChangeRecordTestCase' => 'infrastructure/edges/__tests__/PhabricatorEdgeChangeRecordTestCase.php',
     'PhabricatorEdgeConfig' => 'infrastructure/edges/constants/PhabricatorEdgeConfig.php',
@@ -8829,6 +8830,7 @@
     'PhabricatorDraftDAO' => 'PhabricatorLiskDAO',
     'PhabricatorDraftEngine' => 'Phobject',
     'PhabricatorDrydockApplication' => 'PhabricatorApplication',
+    'PhabricatorDuoFuture' => 'FutureProxy',
     'PhabricatorEdgeChangeRecord' => 'Phobject',
     'PhabricatorEdgeChangeRecordTestCase' => 'PhabricatorTestCase',
     'PhabricatorEdgeConfig' => 'PhabricatorEdgeConstants',
diff --git a/src/applications/auth/future/PhabricatorDuoFuture.php b/src/applications/auth/future/PhabricatorDuoFuture.php
new file mode 100644
--- /dev/null
+++ b/src/applications/auth/future/PhabricatorDuoFuture.php
@@ -0,0 +1,150 @@
+<?php
+
+final class PhabricatorDuoFuture
+  extends FutureProxy {
+
+  private $future;
+
+  private $integrationKey;
+  private $secretKey;
+  private $apiHostname;
+
+  private $httpMethod = 'POST';
+  private $method;
+  private $parameters;
+  private $timeout;
+
+  public function __construct() {
+    parent::__construct(null);
+  }
+
+  public function setIntegrationKey($integration_key) {
+    $this->integrationKey = $integration_key;
+    return $this;
+  }
+
+  public function setSecretKey(PhutilOpaqueEnvelope $key) {
+    $this->secretKey = $key;
+    return $this;
+  }
+
+  public function setAPIHostname($hostname) {
+    $this->apiHostname = $hostname;
+    return $this;
+  }
+
+  public function setMethod($method, array $parameters) {
+    $this->method = $method;
+    $this->parameters = $parameters;
+    return $this;
+  }
+
+  public function setTimeout($timeout) {
+    $this->timeout = $timeout;
+    return $this;
+  }
+
+  public function getTimeout() {
+    return $this->timeout;
+  }
+
+  public function setHTTPMethod($method) {
+    $this->httpMethod = $method;
+    return $this;
+  }
+
+  public function getHTTPMethod() {
+    return $this->httpMethod;
+  }
+
+  protected function getProxiedFuture() {
+    if (!$this->future) {
+      if ($this->integrationKey === null) {
+        throw new PhutilInvalidStateException('setIntegrationKey');
+      }
+
+      if ($this->secretKey === null) {
+        throw new PhutilInvalidStateException('setSecretKey');
+      }
+
+      if ($this->apiHostname === null) {
+        throw new PhutilInvalidStateException('setAPIHostname');
+      }
+
+      if ($this->method === null || $this->parameters === null) {
+        throw new PhutilInvalidStateException('setMethod');
+      }
+
+      $path = (string)urisprintf('/auth/v2/%s', $this->method);
+
+      $host = $this->apiHostname;
+      $host = phutil_utf8_strtolower($host);
+
+      $uri = id(new PhutilURI(''))
+        ->setProtocol('https')
+        ->setDomain($host)
+        ->setPath($path);
+
+      $data = $this->parameters;
+      $date = date('r');
+
+      $http_method = $this->getHTTPMethod();
+
+      ksort($data);
+      $data_parts = array();
+      foreach ($data as $key => $value) {
+        $data_parts[] = rawurlencode($key).'='.rawurlencode($value);
+      }
+      $data_parts = implode('&', $data_parts);
+
+      $corpus = array(
+        $date,
+        $http_method,
+        $host,
+        $path,
+        $data_parts,
+      );
+      $corpus = implode("\n", $corpus);
+
+      $signature = hash_hmac(
+        'sha1',
+        $corpus,
+        $this->secretKey->openEnvelope());
+      $signature = new PhutilOpaqueEnvelope($signature);
+
+      $future = id(new HTTPSFuture($uri, $data))
+        ->setHTTPBasicAuthCredentials($this->integrationKey, $signature)
+        ->setMethod($http_method)
+        ->addHeader('Accept', 'application/json')
+        ->addHeader('Date', $date);
+
+      $timeout = $this->getTimeout();
+      if ($timeout) {
+        $future->setTimeout($timeout);
+      }
+
+      $this->future = $future;
+    }
+
+    return $this->future;
+  }
+
+  protected function didReceiveResult($result) {
+    list($status, $body, $headers) = $result;
+
+    if ($status->isError()) {
+      throw $status;
+    }
+
+    try {
+      $data = phutil_json_decode($body);
+    } catch (PhutilJSONParserException $ex) {
+      throw new PhutilProxyException(
+        pht('Expected JSON response from Duo.'),
+        $ex);
+    }
+
+    return $data;
+  }
+
+}
diff --git a/src/applications/metamta/future/PhabricatorTwilioFuture.php b/src/applications/metamta/future/PhabricatorTwilioFuture.php
--- a/src/applications/metamta/future/PhabricatorTwilioFuture.php
+++ b/src/applications/metamta/future/PhabricatorTwilioFuture.php
@@ -58,7 +58,7 @@
         $this->accountSID,
         $this->method);
 
-      $uri = id(new PhutilURI('https://api.twilio.com/2010-04-01/accounts/'))
+      $uri = id(new PhutilURI('https://api.twilio.com/'))
         ->setPath($path);
 
       $data = $this->parameters;