diff --git a/src/main/java/com/dashjoin/jsonata/Functions.java b/src/main/java/com/dashjoin/jsonata/Functions.java
index e0c1fd0..fceca41 100644
--- a/src/main/java/com/dashjoin/jsonata/Functions.java
+++ b/src/main/java/com/dashjoin/jsonata/Functions.java
@@ -17,6 +17,7 @@
  */
 package com.dashjoin.jsonata;
 
+import java.io.Serializable;
 import java.io.UnsupportedEncodingException;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -63,7 +64,7 @@
 import com.dashjoin.jsonata.utils.DateTimeUtils;
 
 @SuppressWarnings({"rawtypes", "unchecked"})
-public class Functions {
+public class Functions implements Serializable {
 
     /**
      * Sum function
@@ -628,7 +629,7 @@ public static String rightPad(final String str, final int size, String padStr) {
         return str.concat(substr(padding, 0, pads));
     }
 
-    static class RegexpMatch {
+    static class RegexpMatch implements Serializable {
         String match;
         int index;
         List<String> groups;
diff --git a/src/main/java/com/dashjoin/jsonata/Jsonata.java b/src/main/java/com/dashjoin/jsonata/Jsonata.java
index 49587ab..be6bdb0 100644
--- a/src/main/java/com/dashjoin/jsonata/Jsonata.java
+++ b/src/main/java/com/dashjoin/jsonata/Jsonata.java
@@ -24,6 +24,7 @@
  */
 package com.dashjoin.jsonata;
 
+import java.io.Serializable;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
@@ -50,19 +51,19 @@
  * @description JSON query and transformation language
  */
 @SuppressWarnings({"rawtypes", "unchecked"})
-public class Jsonata {
+public class Jsonata implements Serializable {
  
      // Start of Evaluator code
  
-    public static interface EntryCallback {
+    public static interface EntryCallback extends Serializable {
         void callback(Symbol expr, Object input, Frame environment);
     }
 
-    public static interface ExitCallback {
+    public static interface ExitCallback extends Serializable {
         void callback(Symbol expr, Object input, Frame environment, Object result);
     }
 
-    public static class Frame {
+    public static class Frame implements Serializable {
         final Map<String, Object> bindings = new LinkedHashMap<String,Object>();
 
         final Frame parent;
@@ -2099,7 +2100,7 @@ public Frame createFrame(Frame enclosingEnvironment) {
         //  };
     }
 
-    public static interface JLambda {
+    public static interface JLambda extends Serializable {
     }
 
     public static interface FnVarArgs<R> extends JLambda, Function<List<?>, R> {
@@ -2173,18 +2174,18 @@ default JFunctionCallable getJFunctionCallable() {
     /**
      * JFunction callable Lambda interface
      */
-    public static interface JFunctionCallable {
+    public static interface JFunctionCallable extends Serializable {
         Object call(Object input, List args) throws Throwable;
     }
 
-    public static interface JFunctionSignatureValidation {
+    public static interface JFunctionSignatureValidation extends Serializable {
         Object validate(Object args, Object context);
     }
 
     /**
      * JFunction definition class
      */
-    public static class JFunction implements JFunctionCallable, JFunctionSignatureValidation {
+    public static class JFunction implements JFunctionCallable, JFunctionSignatureValidation, Serializable {
         JFunctionCallable function;
         String functionName;
         Signature signature;
diff --git a/src/main/java/com/dashjoin/jsonata/Parser.java b/src/main/java/com/dashjoin/jsonata/Parser.java
index 488e2fe..f2f8cdd 100644
--- a/src/main/java/com/dashjoin/jsonata/Parser.java
+++ b/src/main/java/com/dashjoin/jsonata/Parser.java
@@ -28,6 +28,7 @@
 import java.io.ByteArrayOutputStream;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
+import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -40,7 +41,7 @@
 
 //var parseSignature = require('./signature');
 @SuppressWarnings({"unchecked"})
-public class Parser {
+public class Parser implements Serializable {
 
     boolean dbg = false;
     
@@ -92,7 +93,7 @@ public static<T> T clone(T object) {
         }
     }
     
-    class Symbol implements Cloneable {
+    class Symbol implements Cloneable, Serializable {
 
         //Symbol s;
         String id;
diff --git a/src/main/java/com/dashjoin/jsonata/Timebox.java b/src/main/java/com/dashjoin/jsonata/Timebox.java
index 90ee6da..ea0ca49 100644
--- a/src/main/java/com/dashjoin/jsonata/Timebox.java
+++ b/src/main/java/com/dashjoin/jsonata/Timebox.java
@@ -19,11 +19,13 @@
 
 import com.dashjoin.jsonata.Jsonata.Frame;
 
+import java.io.Serializable;
+
 /**
  * Configure max runtime / max recursion depth.
  * See Frame.setRuntimeBounds - usually not used directly
  */
-public class Timebox {
+public class Timebox implements Serializable {
 
     long timeout = 5000L;
     int maxDepth = 100;
diff --git a/src/main/java/com/dashjoin/jsonata/Tokenizer.java b/src/main/java/com/dashjoin/jsonata/Tokenizer.java
index 503373d..c60c1c1 100644
--- a/src/main/java/com/dashjoin/jsonata/Tokenizer.java
+++ b/src/main/java/com/dashjoin/jsonata/Tokenizer.java
@@ -24,11 +24,12 @@
  */
 package com.dashjoin.jsonata;
 
+import java.io.Serializable;
 import java.util.HashMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-public class Tokenizer { // = function (path) {
+public class Tokenizer implements Serializable { // = function (path) {
 
 static HashMap<String, Integer> operators = new HashMap<String, Integer>() {{
     put(".", 75);
@@ -91,7 +92,7 @@ public class Tokenizer { // = function (path) {
         length = path.length();
     }
 
-    public static class Token {
+    public static class Token implements Serializable {
         String type;
         Object value;
         int position;
diff --git a/src/main/java/com/dashjoin/jsonata/Utils.java b/src/main/java/com/dashjoin/jsonata/Utils.java
index 60bd81c..f5eea54 100644
--- a/src/main/java/com/dashjoin/jsonata/Utils.java
+++ b/src/main/java/com/dashjoin/jsonata/Utils.java
@@ -17,6 +17,7 @@
  */
 package com.dashjoin.jsonata;
 
+import java.io.Serializable;
 import java.util.AbstractList;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -28,7 +29,7 @@
 import com.dashjoin.jsonata.Jsonata.JFunctionCallable;
 
 @SuppressWarnings({"rawtypes"})
-public class Utils {
+public class Utils implements Serializable {
     public static boolean isNumeric(Object v) {
         if (v instanceof Long) return true;
         boolean isNum = false;
@@ -117,7 +118,7 @@ public static boolean isSequence(Object result) {
      * 
      * Used for late materialization of ranges.
      */
-    public static class RangeList extends AbstractList<Number> {
+    public static class RangeList extends AbstractList<Number> implements Serializable {
 
         final long a, b;
         final int size;