diff --git a/src/core/Utils.js b/src/core/Utils.js
index 8e1829f5..3794d972 100755
--- a/src/core/Utils.js
+++ b/src/core/Utils.js
@@ -388,7 +388,7 @@ const Utils = {
         var wordArray = CryptoJS.enc.Utf8.parse(str),
             byteArray = Utils.wordArrayToByteArray(wordArray);
 
-        if (str.length !== wordArray.sigBytes)
+        if (window && str.length !== wordArray.sigBytes)
             window.app.options.attemptHighlight = false;
         return byteArray;
     },
@@ -440,7 +440,7 @@ const Utils = {
             var wordArray = new CryptoJS.lib.WordArray.init(words, byteArray.length),
                 str = CryptoJS.enc.Utf8.stringify(wordArray);
 
-            if (str.length !== wordArray.sigBytes)
+            if (window && str.length !== wordArray.sigBytes)
                 window.app.options.attemptHighlight = false;
             return str;
         } catch (err) {
diff --git a/src/core/operations/URL.js b/src/core/operations/URL.js
index 9dde1798..a00ea9db 100755
--- a/src/core/operations/URL.js
+++ b/src/core/operations/URL.js
@@ -58,6 +58,10 @@ const URL_ = {
      * @returns {string}
      */
     runParse: function(input, args) {
+        if (!document) {
+            throw "This operation only works in a browser.";
+        }
+        
         var a = document.createElement("a");
 
         // Overwrite base href which will be the current CyberChef URL to reduce confusion.
diff --git a/src/core/operations/UUID.js b/src/core/operations/UUID.js
index 3ea0d36d..9302a350 100755
--- a/src/core/operations/UUID.js
+++ b/src/core/operations/UUID.js
@@ -17,7 +17,7 @@ const UUID = {
      * @returns {string}
      */
     runGenerateV4: function(input, args) {
-        if (typeof(window.crypto) !== "undefined" && typeof(window.crypto.getRandomValues) !== "undefined") {
+        if (window && typeof(window.crypto) !== "undefined" && typeof(window.crypto.getRandomValues) !== "undefined") {
             var buf = new Uint32Array(4),
                 i = 0;
             window.crypto.getRandomValues(buf);