diff --git a/icechunk/src/zarr.rs b/icechunk/src/zarr.rs
index f9e871713..28b757446 100644
--- a/icechunk/src/zarr.rs
+++ b/icechunk/src/zarr.rs
@@ -12,7 +12,7 @@ use std::{
 use bytes::Bytes;
 use futures::{Stream, StreamExt, TryStreamExt};
 use itertools::Itertools;
-use serde::{Deserialize, Serialize};
+use serde::{de, Deserialize, Serialize};
 use serde_with::{serde_as, skip_serializing_none, TryFromInto};
 use thiserror::Error;
 
@@ -612,6 +612,7 @@ impl Key {
 #[derive(Debug, Serialize, Deserialize)]
 struct ArrayMetadata {
     zarr_format: u8,
+    #[serde(deserialize_with = "validate_array_node_type")]
     node_type: String,
     attributes: Option<UserAttributes>,
     #[serde(flatten)]
@@ -720,10 +721,43 @@ impl From<ZarrArrayMetadata> for ZarrArrayMetadataSerialzer {
 #[derive(Debug, Serialize, Deserialize)]
 struct GroupMetadata {
     zarr_format: u8,
+    #[serde(deserialize_with = "validate_group_node_type")]
     node_type: String,
     attributes: Option<UserAttributes>,
 }
 
+fn validate_group_node_type<'de, D>(d: D) -> Result<String, D::Error>
+where
+    D: de::Deserializer<'de>,
+{
+    let value = String::deserialize(d)?;
+
+    if value != "group" {
+        return Err(de::Error::invalid_value(
+            de::Unexpected::Str(value.as_str()),
+            &"the word 'group'",
+        ));
+    }
+
+    Ok(value)
+}
+
+fn validate_array_node_type<'de, D>(d: D) -> Result<String, D::Error>
+where
+    D: de::Deserializer<'de>,
+{
+    let value = String::deserialize(d)?;
+
+    if value != "array" {
+        return Err(de::Error::invalid_value(
+            de::Unexpected::Str(value.as_str()),
+            &"the word 'array'",
+        ));
+    }
+
+    Ok(value)
+}
+
 impl ArrayMetadata {
     fn new(attributes: Option<UserAttributes>, zarr_metadata: ZarrArrayMetadata) -> Self {
         Self { zarr_format: 3, node_type: "array".to_string(), attributes, zarr_metadata }
@@ -959,6 +993,27 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_metadata_deserialization() {
+        assert!(serde_json::from_str::<GroupMetadata>(
+            r#"{"zarr_format":3, "node_type":"group"}"#
+        )
+        .is_ok());
+        assert!(serde_json::from_str::<GroupMetadata>(
+            r#"{"zarr_format":3, "node_type":"array"}"#
+        )
+        .is_err());
+
+        assert!(serde_json::from_str::<ArrayMetadata>(
+            r#"{"zarr_format":3,"node_type":"array","shape":[2,2,2],"data_type":"int32","chunk_grid":{"name":"regular","configuration":{"chunk_shape":[1,1,1]}},"chunk_key_encoding":{"name":"default","configuration":{"separator":"/"}},"fill_value":0,"codecs":[{"name":"mycodec","configuration":{"foo":42}}],"storage_transformers":[{"name":"mytransformer","configuration":{"bar":43}}],"dimension_names":["x","y","t"]}"#
+        )
+        .is_ok());
+        assert!(serde_json::from_str::<ArrayMetadata>(
+            r#"{"zarr_format":3,"node_type":"group","shape":[2,2,2],"data_type":"int32","chunk_grid":{"name":"regular","configuration":{"chunk_shape":[1,1,1]}},"chunk_key_encoding":{"name":"default","configuration":{"separator":"/"}},"fill_value":0,"codecs":[{"name":"mycodec","configuration":{"foo":42}}],"storage_transformers":[{"name":"mytransformer","configuration":{"bar":43}}],"dimension_names":["x","y","t"]}"#
+        )
+        .is_err());
+    }
+
     #[tokio::test]
     async fn test_metadata_set_and_get() -> Result<(), Box<dyn std::error::Error>> {
         let storage: Arc<dyn Storage + Send + Sync> =