diff --git a/core/src/commonMain/kotlin/com/powersync/sync/StreamingSyncCheckpointDiff.kt b/core/src/commonMain/kotlin/com/powersync/sync/StreamingSyncCheckpointDiff.kt
index 99f4ebf9..dd83b802 100644
--- a/core/src/commonMain/kotlin/com/powersync/sync/StreamingSyncCheckpointDiff.kt
+++ b/core/src/commonMain/kotlin/com/powersync/sync/StreamingSyncCheckpointDiff.kt
@@ -9,5 +9,5 @@ data class StreamingSyncCheckpointDiff(
     @SerialName("last_op_id") val lastOpId: String,
     @SerialName("updated_buckets") val updatedBuckets: List<BucketChecksum>,
     @SerialName("removed_buckets") val removedBuckets: List<String>,
-    @SerialName("write_checkpoint") val writeCheckpoint: String?
+    @SerialName("write_checkpoint") val writeCheckpoint: String? = null
 )
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