---
title: actorSystemKey
framework: swift
role: symbol
role_heading: Type Property
path: swift/codinguserinfokey/actorsystemkey
---

# actorSystemKey

Key which is required to be set on a Decoder’s userInfo while attempting to init(from:) a DistributedActor. The stored value under this key must conform to DistributedActorSystem.

## Declaration

```swift
static let actorSystemKey: CodingUserInfoKey
```

## Discussion

Discussion Forgetting to set this key will result in that initializer throwing, because an actor system is required in order to call DistributedActor/resolve(id:using:) using it.