diff --git a/CHANGELOG.md b/CHANGELOG.md
index 82df01ad4..2911c191e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+### v3.45.0 (2026-03-09)
+* * *
+### Bug Fixes:
+- Fixed JSON request body serialization to send valid JSON payload for API requests.
+
 ### v3.44.0 (2026-03-02)
 * * *
 ### New Resources:
diff --git a/VERSION b/VERSION
index faf0dcbb0..ff3ff28f6 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-3.44.0
+3.45.0
diff --git a/pom.xml b/pom.xml
index 1f6f8cdda..da3bd9845 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
 
     <groupId>com.chargebee</groupId>
     <artifactId>chargebee-java</artifactId>
-    <version>3.44.0</version>
+    <version>3.45.0</version>
 
 
     <packaging>jar</packaging>
diff --git a/src/main/java/com/chargebee/Environment.java b/src/main/java/com/chargebee/Environment.java
index 61cb4704e..c1c212e5e 100644
--- a/src/main/java/com/chargebee/Environment.java
+++ b/src/main/java/com/chargebee/Environment.java
@@ -37,19 +37,19 @@ public class Environment {
     public static final String CHARSET = "UTF-8";
 
     public static final String API_VERSION = "v2";
-    
-    public static final String LIBRARY_VERSION = "3.44.0";
+
+    public static final String LIBRARY_VERSION = "3.45.0";
 
     private final String apiBaseUrl;
 
     private static Environment defaultEnv; // singleton
-    
+
     private RequestInterceptor reqInterceptor;
-    
+
     public Environment(String siteName, String apiKey) {
         this(siteName, apiKey, null);
     }
-    
+
     public Environment(String siteName, String apiKey, RequestInterceptor reqInterceptor) {
         this.apiKey = apiKey;
         this.siteName = siteName;
@@ -59,15 +59,15 @@ public Environment(String siteName, String apiKey, RequestInterceptor reqInterce
         this.apiBaseUrl = proto + "://" + siteName + "." + domainSuffix + "/api/" + API_VERSION;
         this.retryConfig = RetryConfig.defaultConfig();
     }
-    
+
     public static void configure(String siteName, String apikey) {
         Environment.defaultEnv = new Environment(siteName, apikey);
     }
-    
+
     public static void reqInterceptor(RequestInterceptor reqInterceptor) {
         defaultConfig().reqInterceptor = reqInterceptor;
     }
-    
+
     public RequestInterceptor reqInterceptor() {
         return reqInterceptor;
     }
diff --git a/src/main/java/com/chargebee/internal/Params.java b/src/main/java/com/chargebee/internal/Params.java
index 083b97b2d..e2bfaf2d0 100644
--- a/src/main/java/com/chargebee/internal/Params.java
+++ b/src/main/java/com/chargebee/internal/Params.java
@@ -11,15 +11,18 @@
 public class Params {
 
     private Map<String, Object> m = new HashMap<String, Object>();
+    private Map<String, Object> rawMap = new HashMap<String, Object>();
 
     public void add(String paramName, Object value) {
         if(value == null) {
             throw new RuntimeException("The param {" + paramName + "} cannot be null");
         }
+        rawMap.put(paramName, value);
         m.put(paramName, toValStr(value));
     }
 
     public void addOpt(String paramName, Object value) {
+        rawMap.put(paramName, value);
         m.put(paramName, value != null ? toValStr(value) : "");
     }
 
@@ -45,7 +48,7 @@ public static Object toValStr(Object value) {
             return value.toString();
         } else if (c == Date.class) {
             return new SimpleDateFormat("yyyy-MM-dd").format((Date)value);
-        } 
+        }
         else if(c.isEnum()) {
             return value.toString().toLowerCase();
         } else if(c == Timestamp.class) {
@@ -54,16 +57,16 @@ else if(c.isEnum()) {
             List origList = ((List)value);
             List<String> l = new ArrayList(origList.size());
             for (Object item : origList) {
-                l.add((String)toValStr(item));                
+                l.add((String)toValStr(item));
             }
             return l;
         } else if(value instanceof Object[]){
             Object[] origList = ((Object[])value);
             List<String> l = new ArrayList(origList.length);
             for (Object item : origList) {
-                l.add((String)toValStr(item));                
+                l.add((String)toValStr(item));
             }
-            return l;            
+            return l;
         } else if(value instanceof JSONObject) {
             return value.toString();
         } else if(value instanceof JSONArray) {
@@ -74,7 +77,12 @@ else if(c.isEnum()) {
             throw new RuntimeException("Type [" + c.getName() + "] not handled");
         }
     }
-    
+
+    public String toJson() {
+        JSONObject jsonObject = new JSONObject(rawMap);
+        return jsonObject.toString();
+    }
+
     public static Long asUnixTimestamp(Timestamp ts) {
         return ts.getTime() / 1000;
     }
diff --git a/src/main/java/com/chargebee/internal/Request.java b/src/main/java/com/chargebee/internal/Request.java
index dad5609d9..b65e83d92 100644
--- a/src/main/java/com/chargebee/internal/Request.java
+++ b/src/main/java/com/chargebee/internal/Request.java
@@ -79,7 +79,7 @@ private static Result _request(Environment env, Request<?> req) throws IOExcepti
                     return HttpUtil.post(url, ((BatchRequest<?>) req).buildRequest(), req.headers, env, req.isIdempotent);
                 } else if(req.isJsonRequest){
                     req.headers.put(HttpUtil.CONTENT_TYPE_HEADER_NAME, "application/json;charset=" + Environment.CHARSET);
-                    return HttpUtil.post(url, req.params.toString(), req.headers, env, req.isIdempotent);
+                    return HttpUtil.post(url, req.params.toJson(), req.headers, env, req.isIdempotent);
                 }else {
                     return HttpUtil.post(url, req.params(), req.headers, env, req.isIdempotent);
                 }