diff --git a/kotlin/src/commonMain/kotlin/com/adsbynimbus/openrtb/response/BidResponse.kt b/kotlin/src/commonMain/kotlin/com/adsbynimbus/openrtb/response/BidResponse.kt
index 9f8c5fc..0eba05e 100644
--- a/kotlin/src/commonMain/kotlin/com/adsbynimbus/openrtb/response/BidResponse.kt
+++ b/kotlin/src/commonMain/kotlin/com/adsbynimbus/openrtb/response/BidResponse.kt
@@ -55,7 +55,7 @@ public class BidResponse(
     @JvmField @SerialName("duration") public val duration: Int = 0,
     @JvmField @SerialName("exp") public val exp: Int = -1,
     @JvmField @SerialName("external_notifications") public val external_notifications: Map<String, String> = emptyMap(),
-    @JvmField @SerialName("ext") public val ext: Map<String, String> = emptyMap(),
+    @JvmField @SerialName("ext") public val ext: Extension = Extension(),
 ) {
     /** Urls to fire a request to when an impression is registered */
     public val impression_trackers: Array<String>? get() = trackers["impression_trackers"]
@@ -66,9 +66,6 @@ public class BidResponse(
     /** Url to fire a request to when this bid loses an auction */
     public val loss_response: String? get() = external_notifications["loss_response"]
 
-    public val useNewRenderer: Boolean
-        get() = ext["use_new_renderer"].toBoolean()
-
     public companion object {
         /** Decodes a BidResponse from a Json string using the built in serializer */
         @JvmStatic @JvmOverloads
@@ -84,4 +81,14 @@ public class BidResponse(
             jsonSerializer: Json = BidRequest.lenientSerializer,
         ): String = jsonSerializer.encodeToString(serializer(), response)
     }
+
+    /**
+     * BidResponse Extension object from Nimbus
+     *
+     * @property use_new_renderer Set to false if Nimbus has determined the creative should be rendered using IMA SDK
+     */
+    @Serializable
+    public class Extension(
+        @JvmField @SerialName("use_new_renderer") public val use_new_renderer: Boolean = false,
+    )
 }
diff --git a/kotlin/src/commonTest/kotlin/com/adsbynimbus/openrtb/response/DeserializationTest.kt b/kotlin/src/commonTest/kotlin/com/adsbynimbus/openrtb/response/DeserializationTest.kt
index 1fe4ce1..22d5c2f 100644
--- a/kotlin/src/commonTest/kotlin/com/adsbynimbus/openrtb/response/DeserializationTest.kt
+++ b/kotlin/src/commonTest/kotlin/com/adsbynimbus/openrtb/response/DeserializationTest.kt
@@ -6,7 +6,7 @@ import io.kotest.matchers.shouldBe
 import io.kotest.matchers.string.shouldContain
 import io.kotest.matchers.string.shouldStartWith
 
-const val testJson = """
+private fun testJson(ext: String = "") = """
 {
   "type": "native",
   "auction_id": "d07668d6-35ba-4870-a3cd-02b18fec1a12",
@@ -33,12 +33,13 @@ const val testJson = """
     "win_response": "https://test.adsbynimbus.com/win_response/",
     "loss_response": "https://test.adsbynimbus.com/loss_response/auctionPrice=[AUCTION_PRICE]&auctionMinToWin=[AUCTION_MIN_TO_WIN]&winningSource=[WINNING_SOURCE]"
   }
+  $ext
 }
 """
 
 class DeserializationTest : StringSpec({
 
-    val response = BidResponse.fromJson(testJson)
+    val response = BidResponse.fromJson(testJson())
 
     "BidResponse fromJson deserializes the type field" {
         response.type shouldBe "native"
@@ -104,6 +105,20 @@ class DeserializationTest : StringSpec({
         response.win_response shouldBe "https://test.adsbynimbus.com/win_response/"
     }
 
+    "BidResponse fromJson deserializes use_new_renderer" {
+        response.ext.use_new_renderer shouldBe false
+        BidResponse.fromJson(testJson("""
+            ,"ext": {
+                "use_new_renderer": true
+            }
+        """.trimIndent())).ext.use_new_renderer shouldBe true
+        BidResponse.fromJson(testJson("""
+            ,"ext": {
+                "use_new_renderer": false
+            }
+        """.trimIndent())).ext.use_new_renderer shouldBe false
+    }
+
     "BidResponse fromJson deserializes loss urls" {
         response.loss_response shouldStartWith "https://test.adsbynimbus.com/loss_response/"
         response.loss_response shouldContain "auctionPrice=[AUCTION_PRICE]"