diff --git a/lib/cli.js b/lib/cli.js
index 9b5edd5fe..408500015 100644
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -26,6 +26,15 @@ var validatePathOption = function(optionName, path) {
 	}
 };
 
+var isJsonString = function(str) {
+    try {
+        JSON.parse(str);
+    } catch (e) {
+        return false;
+    }
+    return true;
+};
+
 var cli = nomnom.help(
 	'sitespeed.io is a tool that helps you analyze your website performance and show you what you should optimize, more info at http://www.sitespeed.io.' +
 	EOL +
@@ -404,13 +413,20 @@ var cli = nomnom.help(
 		help: 'The API key if running on webpagetest on the public instances.'
 	},
 	requestHeaders: {
-		metavar: '<FILE>',
-		help: 'Any request headers to use, a file with JSON form of {\"name\":\"value\",\"name2\":\"value\"}. Not supported for WPT & GPSI.',
+		metavar: '<FILE>|<HEADER>',
+		type: 'string',
+		help: 'Any request headers to use, a file or a header string with JSON form of {\"name\":\"value\",\"name2\":\"value\"}. Not supported for WPT & GPSI.',
 		callback: function(path) {
-			return validatePathOption('requestHeaders', path);
+			if (!fs.existsSync(path) && !isJsonString(path)) {
+				return '--requestHeaders: \'' + path + '\' is not a file or not a valid JSON header string!';
+			}
 		},
 		transform: function(path) {
-			return fileHelper.getFileAsJSON(path);
+			if (fs.existsSync(path)) {
+				return fileHelper.getFileAsJSON(path);
+			} else {
+				return JSON.parse(path);
+			}
 		}
 	},
 	postURL: {