# Sandbox.BaseFileSystem.ReadJson

```csharp
T ReadJson(string filename, T defaultValue = null)
```

Read Json from a file using System.Text.Json.JsonSerializer. This will throw exceptions
if not valid json.

### Parameters

- `filename` (`string`)
- `defaultValue` (`T`), default `null`

### Returns

`T`

Declared in [Sandbox.BaseFileSystem](/api/Sandbox.BaseFileSystem).
Assembly: `Sandbox.Filesystem`.