diff --git a/src/future/http/HTTPSFuture.php b/src/future/http/HTTPSFuture.php
--- a/src/future/http/HTTPSFuture.php
+++ b/src/future/http/HTTPSFuture.php
@@ -9,6 +9,7 @@
   private static $results = array();
   private static $pool = array();
   private static $globalCABundle;
+  private static $globalUserCert;
   private static $blindTrustDomains = array();
 
   private $handle;
@@ -118,6 +119,38 @@
   }
 
   /**
+   * Set the global user certificate if one is not specified
+   * for the session, given a path.
+   *
+   * @param string The path to a valid user SSL certificate
+   * @return void
+   */
+  public static function setGlobalUserCertFromPath($path) {
+    self::$globalUserCert = $path;
+  }
+  /**
+   * Set the global user certificate if one is not specified
+   * for the session, given a string.
+   *
+   * @param string The certificate
+   * @return void
+   */
+  public static function setGlobalUserCertFromString($certificate) {
+    $temp = new TempFile();
+    Filesystem::writeFile($temp, $certificate);
+    self::$globalUserCert = $temp;
+  }
+
+  /**
+   * Get the global user SSL certificate
+   *
+   * @return string
+   */
+  public static function getGlobalUserCert() {
+    return self::$globalUserCert;
+  }
+
+  /**
    * Set a list of domains to blindly trust. Certificates for these domains
    * will not be validated.
    *
@@ -346,6 +379,11 @@
         curl_setopt($curl, CURLOPT_CAINFO, $this->getCABundle());
       }
 
+
+      if (self::getGlobalUserCert()) {
+        curl_setopt($curl, CURLOPT_SSLCERT, self::getGlobalUserCert());
+      }
+
       $domain = id(new PhutilURI($uri))->getDomain();
       if (!empty(self::$blindTrustDomains[$domain])) {
         // Disable peer verification for domains that we blindly trust.