diff --git a/bugsnag-plugin-android-ndk/src/main/java/com/bugsnag/android/ndk/OpaqueValue.kt b/bugsnag-plugin-android-ndk/src/main/java/com/bugsnag/android/ndk/OpaqueValue.kt
index 585fa38ae2..3fccb20efc 100644
--- a/bugsnag-plugin-android-ndk/src/main/java/com/bugsnag/android/ndk/OpaqueValue.kt
+++ b/bugsnag-plugin-android-ndk/src/main/java/com/bugsnag/android/ndk/OpaqueValue.kt
@@ -3,6 +3,8 @@ package com.bugsnag.android.ndk
 import com.bugsnag.android.JsonStream
 import java.io.StringWriter
 
+private const val i = 256
+
 /**
  * Marker class for values that are `BSG_METADATA_OPAQUE_VALUE` in the C layer
  */
@@ -10,6 +12,7 @@ internal class OpaqueValue(val json: String) {
     companion object {
         private const val MAX_NDK_STRING_LENGTH = 64
         private const val US_ASCII_MAX_CODEPOINT = 127
+        private const val INITIAL_BUFFER_SIZE = 256
 
         private fun isStringNDKSupported(value: String): Boolean {
             // anything over 63 characters is definitely not supported
@@ -27,7 +30,7 @@ internal class OpaqueValue(val json: String) {
         }
 
         private fun encode(value: Any): String {
-            val writer = StringWriter()
+            val writer = StringWriter(INITIAL_BUFFER_SIZE)
             writer.use { JsonStream(it).value(value, false) }
             return writer.toString()
         }