diff --git a/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/DefaultRequestResponseSerializer.cs b/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/DefaultRequestResponseSerializer.cs
index 7360fa1f075..e8cdac4aae9 100644
--- a/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/DefaultRequestResponseSerializer.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/DefaultRequestResponseSerializer.cs
@@ -95,7 +95,7 @@ internal DefaultRequestResponseSerializerOptionsProvider(IElasticsearchClientSet
 
 	private static IReadOnlyCollection<JsonConverter> CreateDefaultBuiltInConverters(IElasticsearchClientSettings settings) =>
 	[
-		new KeyValuePairConverterFactory(settings),
+		new KeyValuePairConverterFactory(),
 		new ObjectToInferredTypesConverter(),
 		new SourceConverterFactory(settings),
 		new SelfSerializableConverterFactory(settings),
diff --git a/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/KeyValuePairConverter.cs b/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/KeyValuePairConverter.cs
index b68fff3e6cc..f63699803a0 100644
--- a/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/KeyValuePairConverter.cs
+++ b/src/Elastic.Clients.Elasticsearch/_Shared/Serialization/KeyValuePairConverter.cs
@@ -7,16 +7,10 @@
 using System.Text.Json;
 using System.Text.Json.Serialization;
 
-using Elastic.Transport;
-
 namespace Elastic.Clients.Elasticsearch.Serialization;
 
 internal sealed class KeyValuePairConverterFactory : JsonConverterFactory
 {
-	private readonly IElasticsearchClientSettings _settings;
-
-	public KeyValuePairConverterFactory(IElasticsearchClientSettings settings) => _settings = settings;
-
 	public override bool CanConvert(Type typeToConvert) =>
 		typeToConvert.IsGenericType &&
 		typeToConvert.GetGenericTypeDefinition() == typeof(KeyValuePair<,>);
@@ -28,29 +22,25 @@ public override JsonConverter CreateConverter(
 		var itemOneType = type.GetGenericArguments()[0];
 		var itemTwoType = type.GetGenericArguments()[1];
 
-		return (JsonConverter)Activator.CreateInstance(typeof(KeyValuePairConverter<,>).MakeGenericType(itemOneType, itemTwoType), _settings);
+		return (JsonConverter)Activator.CreateInstance(typeof(KeyValuePairConverter<,>).MakeGenericType(itemOneType, itemTwoType));
 	}
 
 	private class KeyValuePairConverter<TItem1, TItem2> : JsonConverter<KeyValuePair<TItem1, TItem2>>
 	{
-		private readonly IElasticsearchClientSettings _settings;
-
-		public KeyValuePairConverter(IElasticsearchClientSettings settings) => _settings = settings;
-
 		public override KeyValuePair<TItem1, TItem2> Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
 		{
 			if (reader.TokenType != JsonTokenType.StartObject)
 				throw new JsonException("Unexpected token for KeyValuePair");
 
 			reader.Read(); // property name (key)
-			var keyString = reader.GetString();
+			var converter = (JsonConverter<TItem1>)options.GetConverter(typeof(TItem1));
+			var key = converter.ReadAsPropertyName(ref reader, typeof(TItem1), options);
 
 			reader.Read(); // value
 			var value = JsonSerializer.Deserialize<TItem2>(ref reader, options);
 
 			reader.Read(); // end object
 
-			var key = (TItem1)Activator.CreateInstance(typeof(TItem1), keyString);
 			return new KeyValuePair<TItem1, TItem2>(key, value);
 		}
 
@@ -59,16 +49,10 @@ public override void Write(Utf8JsonWriter writer, KeyValuePair<TItem1, TItem2> v
 		{
 			writer.WriteStartObject();
 
-			if (value.Key is IUrlParameter parameter)
-			{
-				writer.WritePropertyName(parameter.GetString(_settings));
-			}
-			else
-			{
-				writer.WritePropertyName(value.Key.ToString());
-			}
+			var converter = (JsonConverter<TItem1>)options.GetConverter(typeof(TItem1));
+			converter.WriteAsPropertyName(writer, value.Key, options);
+			JsonSerializer.Serialize(writer, value.Value, options);
 
-			JsonSerializer.Serialize<TItem2>(writer, value.Value, options);
 			writer.WriteEndObject();
 		}
 	}