diff --git a/.changeset/appauth-android-response-values.md b/.changeset/appauth-android-response-values.md
new file mode 100644
index 000000000..c3f68165f
--- /dev/null
+++ b/.changeset/appauth-android-response-values.md
@@ -0,0 +1,5 @@
+---
+"react-native-app-auth": patch
+---
+
+Decode JSON objects and arrays once, preserve nested null values, accept null native values without a crash, and retain scalar/malformed strings. Iterate map entries directly and share the base authorization response serializer when adding a PKCE verifier.
diff --git a/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/MapUtil.java b/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/MapUtil.java
index 624201ad5..4efa65301 100644
--- a/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/MapUtil.java
+++ b/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/MapUtil.java
@@ -15,6 +15,7 @@
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
+import org.json.JSONTokener;
 
 import java.util.HashMap;
 import java.util.Iterator;
@@ -39,24 +40,27 @@ public static HashMap<String, String> readableMapToHashMap(@Nullable ReadableMap
     public static final WritableMap createAdditionalParametersMap(Map<String, String> additionalParameters) {
         WritableMap additionalParametersMap = Arguments.createMap();
 
-        if (!additionalParameters.isEmpty()) {
-
-            Iterator<String> iterator = additionalParameters.keySet().iterator();
-
-            while(iterator.hasNext()) {
-                String key = iterator.next();
-                String value = additionalParameters.get(key);
-                // Try to parse to JSON
+        for (Map.Entry<String, String> entry : additionalParameters.entrySet()) {
+            String key = entry.getKey();
+            String value = entry.getValue();
+            if (value != null) {
                 try {
-                    JSONObject jsonObject = new JSONObject(value);
-                    WritableMap json = convertJsonToMap(jsonObject);
-                    additionalParametersMap.putMap(key, json);
-                    continue;
+                    JSONTokener tokener = new JSONTokener(value);
+                    Object parsed = tokener.nextValue();
+                    if (tokener.nextClean() == 0) {
+                        if (parsed instanceof JSONObject) {
+                            additionalParametersMap.putMap(key, convertJsonToMap((JSONObject) parsed));
+                            continue;
+                        }
+                        if (parsed instanceof JSONArray) {
+                            additionalParametersMap.putArray(key, convertJsonToArray((JSONArray) parsed));
+                            continue;
+                        }
+                    }
                 } catch (JSONException ignored) {
-
                 }
-                additionalParametersMap.putString(key, additionalParameters.get(key));
             }
+            additionalParametersMap.putString(key, value);
         }
 
         return additionalParametersMap;
@@ -69,7 +73,9 @@ private static WritableMap convertJsonToMap(JSONObject jsonObject) throws JSONEx
         while (iterator.hasNext()) {
             String key = iterator.next();
             Object value = jsonObject.get(key);
-            if (value instanceof JSONObject) {
+            if (value == JSONObject.NULL) {
+                map.putNull(key);
+            } else if (value instanceof JSONObject) {
                 map.putMap(key, convertJsonToMap((JSONObject) value));
             } else if (value instanceof JSONArray) {
                 map.putArray(key, convertJsonToArray((JSONArray) value));
@@ -97,7 +103,9 @@ private static WritableArray convertJsonToArray(JSONArray jsonArray) throws JSON
 
         for (int i = 0; i < jsonArray.length(); i++) {
             Object value = jsonArray.get(i);
-            if (value instanceof JSONObject) {
+            if (value == JSONObject.NULL) {
+                array.pushNull();
+            } else if (value instanceof JSONObject) {
                 array.pushMap(convertJsonToMap((JSONObject) value));
             } else if (value instanceof JSONArray) {
                 array.pushArray(convertJsonToArray((JSONArray) value));
diff --git a/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/TokenResponseFactory.java b/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/TokenResponseFactory.java
index 38467ebaa..0b336009a 100644
--- a/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/TokenResponseFactory.java
+++ b/packages/react-native-app-auth/android/src/main/java/com/rnappauth/utils/TokenResponseFactory.java
@@ -91,17 +91,7 @@ public static final WritableMap authorizationResponseToMap(AuthorizationResponse
      * Read raw authorization into a React Native map with codeVerifier value added if present to be passed down the bridge
      */
     public static final WritableMap authorizationCodeResponseToMap(AuthorizationResponse authResponse, String codeVerifier) {
-        WritableMap map = Arguments.createMap();
-        map.putString("authorizationCode", authResponse.authorizationCode);
-        map.putString("accessToken", authResponse.accessToken);
-        map.putMap("additionalParameters", MapUtil.createAdditionalParametersMap(authResponse.additionalParameters));
-        map.putString("idToken", authResponse.idToken);
-        map.putString("tokenType", authResponse.tokenType);
-        map.putArray("scopes", createScopeArray(authResponse.scope));
-
-        if (authResponse.accessTokenExpirationTime != null) {
-            map.putString("accessTokenExpirationTime", DateUtil.formatTimestamp(authResponse.accessTokenExpirationTime));
-        }
+        WritableMap map = authorizationResponseToMap(authResponse);
 
         if (!TextUtils.isEmpty(codeVerifier)) {
             map.putString("codeVerifier", codeVerifier);