How do you work with JSON serialization?

Question

Accepted Answer

**System.Text.Json** — modern JSON library.

**Basic:**
```csharp
// Serialize
var json = JsonSerializer.Serialize(user);

// Deserialize
var user = JsonSerializer.Deserialize<User>(json);
```

**Options:**
```csharp
var options = new JsonSerializerOptions
{
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
    WriteIndented = true
};
var json = JsonSerializer.Serialize(user, options);
```

**Attributes:**
```csharp
[JsonPropertyName("user_name")]
public string UserName { get; set; }

[JsonIgnore]
public string Secret { get; set; }
```

**Key:** System.Text.Json for modern .NET.

C#: How do you work with JSON serialization?