---
title: AppendState
description: JSON Schema for the AppendState action.
---

Append a value to a state array.

```json
{
  "type": "object",
  "properties": {
    "action": {
      "const": "appendState",
      "default": "appendState",
      "type": "string"
    },
    "key": {
      "description": "State key or dot-path to the array",
      "type": "string"
    },
    "value": {
      "description": "Value to append."
    },
    "index": {
      "anyOf": [
        {
          "type": "integer"
        },
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Insert position (int or template string). None to append at end."
    }
  },
  "required": [
    "action",
    "key",
    "value"
  ]
}
```
