docs/guide/csharp/basic-serialization.md

---
title: Basic Serialization
sidebar_position: 1
id: basic_serialization
license: |
  Licensed to the Apache Software Foundation (ASF) under one or more
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  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
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---

This page covers typed serialization APIs in Apache Fory™ C#.

## Object Graph Serialization

Use `[ForyStruct]` on your classes/structs and register them before use.

```csharp
using Apache.Fory;

[ForyStruct]
public sealed class Address
{
    public string Street { get; set; } = string.Empty;
    public int Zip { get; set; }
}

[ForyStruct]
public sealed class Person
{
    public long Id { get; set; }
    public string Name { get; set; } = string.Empty;
    public string? Nickname { get; set; }
    public List<int> Scores { get; set; } = [];
    public List<Address> Addresses { get; set; } = [];
}

Fory fory = Fory.Builder().Build();
fory.Register<Address>(100);
fory.Register<Person>(101);

Person person = new()
{
    Id = 42,
    Name = "Alice",
    Nickname = null,
    Scores = [10, 20, 30],
    Addresses = [new Address { Street = "Main", Zip = 94107 }],
};

byte[] payload = fory.Serialize(person);
Person decoded = fory.Deserialize<Person>(payload);
```

## Typed API

### Serialize / Deserialize with byte arrays

```csharp
byte[] payload = fory.Serialize(value);
MyType decoded = fory.Deserialize<MyType>(payload);
```

### Deserialize from `ReadOnlySpan<byte>`

```csharp
ReadOnlySpan<byte> span = payload;
MyType decoded = fory.Deserialize<MyType>(span);
```

### Stream-style frame consumption

```csharp
using System.Buffers;

ReadOnlySequence<byte> sequence = GetFramedSequence();
MyType first = fory.Deserialize<MyType>(ref sequence);
MyType second = fory.Deserialize<MyType>(ref sequence);
```

## Dynamic Payloads via Generic Object API

When the compile-time type is unknown or heterogeneous, use the generic API with `object?`.

```csharp
Dictionary<object, object?> value = new()
{
    ["k1"] = 7,
    [2] = "v2",
    [true] = null,
};

byte[] payload = fory.Serialize<object?>(value);
object? decoded = fory.Deserialize<object?>(payload);
```

Dynamic maps normally decode as `Dictionary<object, object?>` when they have no
null key. If the payload uses reference tracking for the dynamic map itself, C#
returns `NullableKeyDictionary<object, object?>` so nested references and null
keys point to the decoded map owner.

## Buffer Writer API

Serialize directly into `IBufferWriter<byte>` targets.

```csharp
using System.Buffers;

ArrayBufferWriter<byte> writer = new();
fory.Serialize(writer, value);

ArrayBufferWriter<byte> dynamicWriter = new();
fory.Serialize<object?>(dynamicWriter, value);
```

## Notes

- Reuse the same `Fory` or `ThreadSafeFory` instance for better performance.
- Primitive types and collections do not require user registration.
- User `[ForyStruct]`, `[ForyEnum]`, `[ForyUnion]`, and custom serializer types should be registered explicitly.

## Related Topics

- [Type Registration](type-registration.md)
- [Supported Types](supported-types.md)
- [References](references.md)