diff --git a/core-api/src/main/java/com/optimizely/ab/config/FeatureVariable.java b/core-api/src/main/java/com/optimizely/ab/config/FeatureVariable.java
index 7d8657970..92d082a08 100644
--- a/core-api/src/main/java/com/optimizely/ab/config/FeatureVariable.java
+++ b/core-api/src/main/java/com/optimizely/ab/config/FeatureVariable.java
@@ -65,12 +65,15 @@ public static VariableStatus fromString(String variableStatusString) {
     public static final String INTEGER_TYPE = "integer";
     public static final String DOUBLE_TYPE = "double";
     public static final String BOOLEAN_TYPE = "boolean";
+    public static final String JSON_TYPE = "json";
 
     private final String id;
     private final String key;
     private final String defaultValue;
     private final String type;
     @Nullable
+    private final String subType;        // this is for backward-compatibility (json type)
+    @Nullable
     private final VariableStatus status;
 
     @JsonCreator
@@ -78,12 +81,14 @@ public FeatureVariable(@JsonProperty("id") String id,
                            @JsonProperty("key") String key,
                            @JsonProperty("defaultValue") String defaultValue,
                            @JsonProperty("status") VariableStatus status,
-                           @JsonProperty("type") String type) {
+                           @JsonProperty("type") String type,
+                           @JsonProperty("subType") String subType) {
         this.id = id;
         this.key = key;
         this.defaultValue = defaultValue;
         this.status = status;
         this.type = type;
+        this.subType = subType;
     }
 
     @Nullable
@@ -104,6 +109,7 @@ public String getDefaultValue() {
     }
 
     public String getType() {
+        if (type.equals(STRING_TYPE) && subType != null && subType.equals(JSON_TYPE)) return JSON_TYPE;
         return type;
     }
 
@@ -114,6 +120,7 @@ public String toString() {
             ", key='" + key + '\'' +
             ", defaultValue='" + defaultValue + '\'' +
             ", type=" + type +
+            ", subType=" + subType +
             ", status=" + status +
             '}';
     }
@@ -138,7 +145,8 @@ public int hashCode() {
         result = 31 * result + key.hashCode();
         result = 31 * result + defaultValue.hashCode();
         result = 31 * result + type.hashCode();
-        result = 31 * result + status.hashCode();
+        result = 31 * result + (subType != null ? subType.hashCode() : 0);
+        result = 31 * result + (status != null ? status.hashCode() : 0);
         return result;
     }
 }
diff --git a/core-api/src/main/java/com/optimizely/ab/config/parser/JsonConfigParser.java b/core-api/src/main/java/com/optimizely/ab/config/parser/JsonConfigParser.java
index 21198da06..0e33ad4b2 100644
--- a/core-api/src/main/java/com/optimizely/ab/config/parser/JsonConfigParser.java
+++ b/core-api/src/main/java/com/optimizely/ab/config/parser/JsonConfigParser.java
@@ -345,12 +345,16 @@ private List<FeatureVariable> parseFeatureVariables(JSONArray featureVariablesJs
             String key = FeatureVariableObject.getString("key");
             String defaultValue = FeatureVariableObject.getString("defaultValue");
             String type = FeatureVariableObject.getString("type");
+            String subType = null;
+            if (FeatureVariableObject.has("subType")) {
+                subType = FeatureVariableObject.getString("subType");
+            }
             FeatureVariable.VariableStatus status = null;
             if (FeatureVariableObject.has("status")) {
                 status = FeatureVariable.VariableStatus.fromString(FeatureVariableObject.getString("status"));
             }
 
-            featureVariables.add(new FeatureVariable(id, key, defaultValue, status, type));
+            featureVariables.add(new FeatureVariable(id, key, defaultValue, status, type, subType));
         }
 
         return featureVariables;
diff --git a/core-api/src/main/java/com/optimizely/ab/config/parser/JsonSimpleConfigParser.java b/core-api/src/main/java/com/optimizely/ab/config/parser/JsonSimpleConfigParser.java
index f800595e3..24180c61a 100644
--- a/core-api/src/main/java/com/optimizely/ab/config/parser/JsonSimpleConfigParser.java
+++ b/core-api/src/main/java/com/optimizely/ab/config/parser/JsonSimpleConfigParser.java
@@ -335,9 +335,10 @@ private List<FeatureVariable> parseFeatureVariables(JSONArray featureVariablesJs
             String key = (String) featureVariableObject.get("key");
             String defaultValue = (String) featureVariableObject.get("defaultValue");
             String type = (String) featureVariableObject.get("type");
+            String subType = (String) featureVariableObject.get("subType");
             VariableStatus status = VariableStatus.fromString((String) featureVariableObject.get("status"));
 
-            featureVariables.add(new FeatureVariable(id, key, defaultValue, status, type));
+            featureVariables.add(new FeatureVariable(id, key, defaultValue, status, type, subType));
         }
 
         return featureVariables;
diff --git a/core-api/src/test/java/com/optimizely/ab/config/ValidProjectConfigV4.java b/core-api/src/test/java/com/optimizely/ab/config/ValidProjectConfigV4.java
index dd79294b8..1c71667f8 100644
--- a/core-api/src/test/java/com/optimizely/ab/config/ValidProjectConfigV4.java
+++ b/core-api/src/test/java/com/optimizely/ab/config/ValidProjectConfigV4.java
@@ -247,7 +247,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_DOUBLE_VARIABLE_KEY,
         VARIABLE_DOUBLE_DEFAULT_VALUE,
         null,
-        FeatureVariable.DOUBLE_TYPE
+        FeatureVariable.DOUBLE_TYPE,
+        null
     );
     private static final String FEATURE_SINGLE_VARIABLE_INTEGER_ID = "3281420120";
     public static final String FEATURE_SINGLE_VARIABLE_INTEGER_KEY = "integer_single_variable_feature";
@@ -259,7 +260,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_INTEGER_VARIABLE_KEY,
         VARIABLE_INTEGER_DEFAULT_VALUE,
         null,
-        FeatureVariable.INTEGER_TYPE
+        FeatureVariable.INTEGER_TYPE,
+        null
     );
     private static final String FEATURE_SINGLE_VARIABLE_BOOLEAN_ID = "2591051011";
     public static final String FEATURE_SINGLE_VARIABLE_BOOLEAN_KEY = "boolean_single_variable_feature";
@@ -271,7 +273,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_BOOLEAN_VARIABLE_KEY,
         VARIABLE_BOOLEAN_VARIABLE_DEFAULT_VALUE,
         null,
-        FeatureVariable.BOOLEAN_TYPE
+        FeatureVariable.BOOLEAN_TYPE,
+        null
     );
     private static final FeatureFlag FEATURE_FLAG_SINGLE_VARIABLE_BOOLEAN = new FeatureFlag(
         FEATURE_SINGLE_VARIABLE_BOOLEAN_ID,
@@ -292,7 +295,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_STRING_VARIABLE_KEY,
         VARIABLE_STRING_VARIABLE_DEFAULT_VALUE,
         null,
-        FeatureVariable.STRING_TYPE
+        FeatureVariable.STRING_TYPE,
+        null
     );
     private static final String ROLLOUT_1_ID = "1058508303";
     private static final String ROLLOUT_1_EVERYONE_ELSE_EXPERIMENT_ID = "1785077004";
@@ -388,7 +392,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_FIRST_LETTER_KEY,
         VARIABLE_FIRST_LETTER_DEFAULT_VALUE,
         null,
-        FeatureVariable.STRING_TYPE
+        FeatureVariable.STRING_TYPE,
+        null
     );
     private static final String VARIABLE_REST_OF_NAME_ID = "4052219963";
     private static final String VARIABLE_REST_OF_NAME_KEY = "rest_of_name";
@@ -398,9 +403,32 @@ public class ValidProjectConfigV4 {
         VARIABLE_REST_OF_NAME_KEY,
         VARIABLE_REST_OF_NAME_DEFAULT_VALUE,
         null,
-        FeatureVariable.STRING_TYPE
+        FeatureVariable.STRING_TYPE,
+        null
+    );
+    private static final String VARIABLE_JSON_PATCHED_TYPE_ID = "4111661000";
+    private static final String VARIABLE_JSON_PATCHED_TYPE_KEY = "json_patched";
+    private static final String VARIABLE_JSON_PATCHED_TYPE_DEFAULT_VALUE = "{\"k1\":\"v1\",\"k2\":3.5,\"k3\":true,\"k4\":{\"kk1\":\"vv1\",\"kk2\":false}}";
+    private static final FeatureVariable VARIABLE_JSON_PATCHED_TYPE_VARIABLE = new FeatureVariable(
+        VARIABLE_JSON_PATCHED_TYPE_ID,
+        VARIABLE_JSON_PATCHED_TYPE_KEY,
+        VARIABLE_JSON_PATCHED_TYPE_DEFAULT_VALUE,
+        null,
+        FeatureVariable.STRING_TYPE,
+        FeatureVariable.JSON_TYPE
+    );
+    private static final String VARIABLE_JSON_NATIVE_TYPE_ID = "4111661001";
+    private static final String VARIABLE_JSON_NATIVE_TYPE_KEY = "json_native";
+    private static final String VARIABLE_JSON_NATIVE_TYPE_DEFAULT_VALUE = "{\"k1\":\"v1\",\"k2\":3.5,\"k3\":true,\"k4\":{\"kk1\":\"vv1\",\"kk2\":false}}";
+    private static final FeatureVariable VARIABLE_JSON_NATIVE_TYPE_VARIABLE = new FeatureVariable(
+        VARIABLE_JSON_NATIVE_TYPE_ID,
+        VARIABLE_JSON_NATIVE_TYPE_KEY,
+        VARIABLE_JSON_NATIVE_TYPE_DEFAULT_VALUE,
+        null,
+        FeatureVariable.JSON_TYPE,
+        null
     );
-    private static final String VARIABLE_FUTURE_TYPE_ID = "4111661234";
+    private static final String VARIABLE_FUTURE_TYPE_ID = "4111661002";
     private static final String VARIABLE_FUTURE_TYPE_KEY = "future_variable";
     private static final String VARIABLE_FUTURE_TYPE_DEFAULT_VALUE = "future_value";
     private static final FeatureVariable VARIABLE_FUTURE_TYPE_VARIABLE = new FeatureVariable(
@@ -408,7 +436,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_FUTURE_TYPE_KEY,
         VARIABLE_FUTURE_TYPE_DEFAULT_VALUE,
         null,
-        "future_type"
+        "future_type",
+        null
     );
     private static final String FEATURE_MUTEX_GROUP_FEATURE_ID = "3263342226";
     public static final String FEATURE_MUTEX_GROUP_FEATURE_KEY = "mutex_group_feature";
@@ -420,7 +449,8 @@ public class ValidProjectConfigV4 {
         VARIABLE_CORRELATING_VARIATION_NAME_KEY,
         VARIABLE_CORRELATING_VARIATION_NAME_DEFAULT_VALUE,
         null,
-        FeatureVariable.STRING_TYPE
+        FeatureVariable.STRING_TYPE,
+        null
     );
 
     // group IDs
@@ -733,6 +763,10 @@ public class ValidProjectConfigV4 {
             new FeatureVariableUsageInstance(
                 VARIABLE_REST_OF_NAME_ID,
                 "red"
+            ),
+            new FeatureVariableUsageInstance(
+                VARIABLE_JSON_PATCHED_TYPE_ID,
+                "{\"k1\":\"s1\",\"k2\":103.5,\"k3\":false,\"k4\":{\"kk1\":\"ss1\",\"kk2\":true}}"
             )
         )
     );
@@ -750,6 +784,10 @@ public class ValidProjectConfigV4 {
             new FeatureVariableUsageInstance(
                 VARIABLE_REST_OF_NAME_ID,
                 "eorge"
+            ),
+            new FeatureVariableUsageInstance(
+                VARIABLE_JSON_PATCHED_TYPE_ID,
+                "{\"k1\":\"s2\",\"k2\":203.5,\"k3\":true,\"k4\":{\"kk1\":\"ss2\",\"kk2\":true}}"
             )
         )
     );
@@ -768,6 +806,10 @@ public class ValidProjectConfigV4 {
             new FeatureVariableUsageInstance(
                 VARIABLE_REST_OF_NAME_ID,
                 "red"
+            ),
+            new FeatureVariableUsageInstance(
+                VARIABLE_JSON_PATCHED_TYPE_ID,
+                "{\"k1\":\"s3\",\"k2\":303.5,\"k3\":true,\"k4\":{\"kk1\":\"ss3\",\"kk2\":false}}"
             )
         )
     );
@@ -785,6 +827,10 @@ public class ValidProjectConfigV4 {
             new FeatureVariableUsageInstance(
                 VARIABLE_REST_OF_NAME_ID,
                 "eorge"
+            ),
+            new FeatureVariableUsageInstance(
+                VARIABLE_JSON_PATCHED_TYPE_ID,
+                "{\"k1\":\"s4\",\"k2\":403.5,\"k3\":false,\"k4\":{\"kk1\":\"ss4\",\"kk2\":true}}"
             )
         )
     );
@@ -1262,6 +1308,8 @@ public class ValidProjectConfigV4 {
         DatafileProjectConfigTestUtils.createListOfObjects(
             VARIABLE_FIRST_LETTER_VARIABLE,
             VARIABLE_REST_OF_NAME_VARIABLE,
+            VARIABLE_JSON_PATCHED_TYPE_VARIABLE,
+            VARIABLE_JSON_NATIVE_TYPE_VARIABLE,
             VARIABLE_FUTURE_TYPE_VARIABLE
         )
     );
diff --git a/core-api/src/test/java/com/optimizely/ab/config/parser/GsonConfigParserTest.java b/core-api/src/test/java/com/optimizely/ab/config/parser/GsonConfigParserTest.java
index c6d5807bc..de2ac643a 100644
--- a/core-api/src/test/java/com/optimizely/ab/config/parser/GsonConfigParserTest.java
+++ b/core-api/src/test/java/com/optimizely/ab/config/parser/GsonConfigParserTest.java
@@ -21,6 +21,8 @@
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.reflect.TypeToken;
+import com.optimizely.ab.config.FeatureFlag;
+import com.optimizely.ab.config.FeatureVariable;
 import com.optimizely.ab.config.ProjectConfig;
 import com.optimizely.ab.config.audience.Audience;
 import com.optimizely.ab.config.audience.Condition;
@@ -42,6 +44,7 @@
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV3;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV4;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.verifyProjectConfig;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 
 /**
@@ -92,6 +95,45 @@ public void parseNullFeatureEnabledProjectConfigV4() throws Exception {
 
     }
 
+    @Test
+    public void parseFeatureVariablesWithJsonPatched() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // "string" type + "json" subType
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_patched");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithJsonNative() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // native "json" type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_native");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithFutureType() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // unknown type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("future_variable");
+
+        assertEquals(variable.getType(), "future_type");
+    }
+
     @Test
     public void parseAudience() throws Exception {
         JsonObject jsonObject = new JsonObject();
diff --git a/core-api/src/test/java/com/optimizely/ab/config/parser/JacksonConfigParserTest.java b/core-api/src/test/java/com/optimizely/ab/config/parser/JacksonConfigParserTest.java
index bca3ebb9a..61c44e730 100644
--- a/core-api/src/test/java/com/optimizely/ab/config/parser/JacksonConfigParserTest.java
+++ b/core-api/src/test/java/com/optimizely/ab/config/parser/JacksonConfigParserTest.java
@@ -18,6 +18,8 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.optimizely.ab.config.FeatureFlag;
+import com.optimizely.ab.config.FeatureVariable;
 import com.optimizely.ab.config.ProjectConfig;
 import com.optimizely.ab.config.audience.Audience;
 import com.optimizely.ab.config.audience.Condition;
@@ -36,6 +38,7 @@
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV3;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV4;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.verifyProjectConfig;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 
 /**
@@ -86,6 +89,44 @@ public void parseNullFeatureEnabledProjectConfigV4() throws Exception {
 
     }
 
+    @Test
+    public void parseFeatureVariablesWithJsonPatched() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // "string" type + "json" subType
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_patched");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithJsonNative() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // native "json" type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_native");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithFutureType() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // unknown type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("future_variable");
+
+        assertEquals(variable.getType(), "future_type");
+    }
 
     @Test
     public void parseAudience() throws Exception {
diff --git a/core-api/src/test/java/com/optimizely/ab/config/parser/JsonConfigParserTest.java b/core-api/src/test/java/com/optimizely/ab/config/parser/JsonConfigParserTest.java
index 9e2b52e8e..27995b88f 100644
--- a/core-api/src/test/java/com/optimizely/ab/config/parser/JsonConfigParserTest.java
+++ b/core-api/src/test/java/com/optimizely/ab/config/parser/JsonConfigParserTest.java
@@ -16,6 +16,8 @@
  */
 package com.optimizely.ab.config.parser;
 
+import com.optimizely.ab.config.FeatureFlag;
+import com.optimizely.ab.config.FeatureVariable;
 import com.optimizely.ab.config.ProjectConfig;
 
 import com.optimizely.ab.config.audience.AudienceIdCondition;
@@ -38,6 +40,7 @@
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV3;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV4;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.verifyProjectConfig;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 
 /**
@@ -88,6 +91,45 @@ public void parseNullFeatureEnabledProjectConfigV4() throws Exception {
 
     }
 
+    @Test
+    public void parseFeatureVariablesWithJsonPatched() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // "string" type + "json" subType
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_patched");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithJsonNative() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // native "json" type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_native");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithFutureType() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // unknown type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("future_variable");
+
+        assertEquals(variable.getType(), "future_type");
+    }
+
     @Test
     public void parseAudience() throws Exception {
         JSONObject jsonObject = new JSONObject();
diff --git a/core-api/src/test/java/com/optimizely/ab/config/parser/JsonSimpleConfigParserTest.java b/core-api/src/test/java/com/optimizely/ab/config/parser/JsonSimpleConfigParserTest.java
index d95b52500..e22192291 100644
--- a/core-api/src/test/java/com/optimizely/ab/config/parser/JsonSimpleConfigParserTest.java
+++ b/core-api/src/test/java/com/optimizely/ab/config/parser/JsonSimpleConfigParserTest.java
@@ -16,6 +16,8 @@
  */
 package com.optimizely.ab.config.parser;
 
+import com.optimizely.ab.config.FeatureFlag;
+import com.optimizely.ab.config.FeatureVariable;
 import com.optimizely.ab.config.ProjectConfig;
 
 import com.optimizely.ab.config.audience.AudienceIdCondition;
@@ -30,6 +32,8 @@
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
 
+import java.util.List;
+
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.nullFeatureEnabledConfigJsonV4;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validConfigJsonV2;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validConfigJsonV4;
@@ -38,6 +42,7 @@
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV3;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.validProjectConfigV4;
 import static com.optimizely.ab.config.DatafileProjectConfigTestUtils.verifyProjectConfig;
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 
 /**
@@ -88,6 +93,45 @@ public void parseNullFeatureEnabledProjectConfigV4() throws Exception {
 
     }
 
+    @Test
+    public void parseFeatureVariablesWithJsonPatched() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // "string" type + "json" subType
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_patched");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithJsonNative() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // native "json" type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("json_native");
+
+        assertEquals(variable.getType(), "json");
+    }
+
+    @Test
+    public void parseFeatureVariablesWithFutureType() throws Exception {
+        JsonSimpleConfigParser parser = new JsonSimpleConfigParser();
+        ProjectConfig actual = parser.parseProjectConfig(validConfigJsonV4());
+
+        // unknown type
+
+        FeatureFlag featureFlag = actual.getFeatureKeyMapping().get("multi_variate_feature");
+        FeatureVariable variable = featureFlag.getVariableKeyToFeatureVariableMap().get("future_variable");
+
+        assertEquals(variable.getType(), "future_type");
+    }
+
     @Test
     public void parseAudience() throws Exception {
         JSONObject jsonObject = new JSONObject();
diff --git a/core-api/src/test/java/com/optimizely/ab/optimizelyconfig/OptimizelyConfigServiceTest.java b/core-api/src/test/java/com/optimizely/ab/optimizelyconfig/OptimizelyConfigServiceTest.java
index 44808c93b..94058776b 100644
--- a/core-api/src/test/java/com/optimizely/ab/optimizelyconfig/OptimizelyConfigServiceTest.java
+++ b/core-api/src/test/java/com/optimizely/ab/optimizelyconfig/OptimizelyConfigServiceTest.java
@@ -287,14 +287,16 @@ private ProjectConfig generateOptimizelyConfig() {
                             "first_letter",
                             "H",
                             FeatureVariable.VariableStatus.ACTIVE,
-                            FeatureVariable.STRING_TYPE
+                            FeatureVariable.STRING_TYPE,
+                            null
                         ),
                         new FeatureVariable(
                             "4052219963",
                             "rest_of_name",
                             "arry",
                             FeatureVariable.VariableStatus.ACTIVE,
-                            FeatureVariable.STRING_TYPE
+                            FeatureVariable.STRING_TYPE,
+                            null
                         )
                     )
                 )
diff --git a/core-api/src/test/resources/config/valid-project-config-v4.json b/core-api/src/test/resources/config/valid-project-config-v4.json
index 293b26cc7..455a5e8bf 100644
--- a/core-api/src/test/resources/config/valid-project-config-v4.json
+++ b/core-api/src/test/resources/config/valid-project-config-v4.json
@@ -271,6 +271,10 @@
             {
               "id": "4052219963",
               "value": "red"
+            },
+            {
+              "id": "4111661000",
+              "value": "{\"k1\":\"s1\",\"k2\":103.5,\"k3\":false,\"k4\":{\"kk1\":\"ss1\",\"kk2\":true}}"
             }
           ]
         },
@@ -286,6 +290,10 @@
             {
               "id": "4052219963",
               "value": "eorge"
+            },
+            {
+              "id": "4111661000",
+              "value": "{\"k1\":\"s2\",\"k2\":203.5,\"k3\":true,\"k4\":{\"kk1\":\"ss2\",\"kk2\":true}}"
             }
           ]
         },
@@ -301,6 +309,10 @@
             {
               "id": "4052219963",
               "value": "red"
+            },
+            {
+              "id": "4111661000",
+              "value": "{\"k1\":\"s3\",\"k2\":303.5,\"k3\":true,\"k4\":{\"kk1\":\"ss3\",\"kk2\":false}}"
             }
           ]
         },
@@ -316,6 +328,10 @@
             {
               "id": "4052219963",
               "value": "eorge"
+            },
+            {
+              "id": "4111661000",
+              "value": "{\"k1\":\"s4\",\"k2\":403.5,\"k3\":false,\"k4\":{\"kk1\":\"ss4\",\"kk2\":true}}"
             }
           ]
         }
@@ -695,7 +711,20 @@
           "defaultValue": "arry"
         },
         {
-          "id": "4111661234",
+          "id": "4111661000",
+          "key": "json_patched",
+          "type": "string",
+          "subType": "json",
+          "defaultValue": "{\"k1\":\"v1\",\"k2\":3.5,\"k3\":true,\"k4\":{\"kk1\":\"vv1\",\"kk2\":false}}"
+        },
+        {
+          "id": "4111661001",
+          "key": "json_native",
+          "type": "json",
+          "defaultValue": "{\"k1\":\"v1\",\"k2\":3.5,\"k3\":true,\"k4\":{\"kk1\":\"vv1\",\"kk2\":false}}"
+        },
+        {
+          "id": "4111661002",
           "key": "future_variable",
           "type": "future_type",
           "defaultValue": "future_value"