diff --git a/chrome/content/zotero/xpcom/translation/translate.js b/chrome/content/zotero/xpcom/translation/translate.js
index a98cfd9ece..268c3e7a54 100644
--- a/chrome/content/zotero/xpcom/translation/translate.js
+++ b/chrome/content/zotero/xpcom/translation/translate.js
@@ -2053,6 +2053,13 @@ Zotero.Translate.Web.prototype.setCookieSandbox = function(cookieSandbox) {
 	this.cookieSandbox = cookieSandbox;
 }
 
+/**
+ * Sets headers to include in HTTP requests. Used by translation-server.
+ */
+Zotero.Translate.Web.prototype.setRequestHeaders = function (headers) {
+	this.requestHeaders = headers;
+};
+
 /**
  * Sets the location to operate upon
  *
diff --git a/chrome/content/zotero/xpcom/utilities_translate.js b/chrome/content/zotero/xpcom/utilities_translate.js
index 89ea3e57dd..630e644068 100644
--- a/chrome/content/zotero/xpcom/utilities_translate.js
+++ b/chrome/content/zotero/xpcom/utilities_translate.js
@@ -360,7 +360,7 @@ Zotero.Utilities.Translate.prototype.doGet = function(urls, processor, done, res
 		} catch(e) {
 			translate.complete(false, e);
 		}
-	}, responseCharset, this._translate.cookieSandbox, requestHeaders);
+	}, responseCharset, this._translate.cookieSandbox, Object.assign({}, this._translate.requestHeaders, requestHeaders));
 }
 
 /**
@@ -393,7 +393,7 @@ Zotero.Utilities.Translate.prototype.doPost = function(url, body, onDone, header
 		} catch(e) {
 			translate.complete(false, e);
 		}
-	}, headers, responseCharset, translate.cookieSandbox ? translate.cookieSandbox : undefined);
+	}, Object.assign({}, translate.requestHeaders, headers), responseCharset, translate.cookieSandbox ? translate.cookieSandbox : undefined);
 }
 
 Zotero.Utilities.Translate.prototype.urlToProxy = function(url) {