---
title: Serialization of Elasticsearch types
description: Normally, it is not necessary to manually serialize or deserialize internal Elastic.Clients.Elasticsearch types. In rare cases, however, it may still...
url: https://www.elastic.co/docs/reference/elasticsearch/clients/dotnet/request-response-serialization
products:
  - Elasticsearch
  - Elasticsearch .NET Client
  - Elasticsearch Client
---

# Serialization of Elasticsearch types
Normally, it is not necessary to manually serialize or deserialize internal `Elastic.Clients.Elasticsearch` types. In rare cases, however, it may still be useful to do so.
<warning>
  We strongly advise against persisting serialized Elasticsearch types, as their structure may vary between different versions of the client.Instead, you should create your own POCO type and map/assign the desired properties to it.
</warning>


## Serializing Elasticsearch types

The default `System.Text.Json` serializer does not know how to serialize `Elastic.Clients.Elasticsearch` types. Therefore, (de-)serialization must be delegated to the built in `RequestResponseSerializer` of the client.

### Serialization

```csharp
using Elastic.Clients.Elasticsearch;
using Elastic.Transport.Extensions;

var query = new Query
{
    Match = new MatchQuery
    {
        Field = Infer.Field<Person>(p => p.FirstName),
        Query = "Florian"
    }
};

var json = client.RequestResponseSerializer.SerializeToString(query); 
```


### Deserialization

```csharp
using Elastic.Clients.Elasticsearch;
using Elastic.Transport.Extensions;

var json = """
{
  "match": {
    "firstName": {
      "query": "Florian"
    }
  }
}
""";

var query = client.RequestResponseSerializer.Deserialize<Query>(json)!; 
```


## Serializing Elasticsearch descriptor types

Descriptor types do not support direct (de-)serialization.
However, starting with client versions 8.19 and 9.0, descriptor types support bidirectional conversion to/from the corresponding object representation.
We can use this functionality to indirectly (de)serialize descriptor types.

### Serialization

```csharp
using Elastic.Clients.Elasticsearch;
using Elastic.Transport.Extensions;

var requestDescriptor = new SearchRequestDescriptor<Person>()
    .Query(q => q
        .Match(m => m
            .Field(p => p.FirstName)
            .Query("Florian")
        )
    );

var request = (SearchRequest)requestDescriptor; 
var json = client.RequestResponseSerializer.SerializeToString(request); 
```


### Deserialization

```csharp
using Elastic.Clients.Elasticsearch;
using Elastic.Transport.Extensions;

var json = """
{
  "query": {
    "match": {
      "firstName": {
        "query": "Florian"
      }
    }
  }
}
""";

var request = client.RequestResponseSerializer.Deserialize<SearchRequest>(json)!; 
var requestDescriptor = new SearchRequestDescriptor<Person>(request); 
```


## Remarks

In addition to `SerializeToString()` and `Deserialize<T>()`, the `Elastic.Transport.Extensions` namespace offers several other extension methods related to (de)serialization.

## Limitations for request and response types

The (de)serialization of Elasticsearch request and response types is subject to certain limitations:
In addition to *body*-related properties, request types also have properties whose values are used in the HTTP *path* or *query* segment.
These properties are **not** taken into account during serialization. The result of serialization represents only the *body* of the request.
<warning>
  When deserializing a request type, it may happen that otherwise required path or query parameters are not initialized. These properties must be manually assigned before using the request.
</warning>

A few request and response types in Elasticsearch do not support JSON bodies and therefore cannot be serialized in the above described way.
Two prominent examples are the `Bulk` or `MultiGet` APIs, which use NDJSON bodies. Binary responses also occur in some cases.