# ExtAppEngine

Location: [gRPC API](https://developer.m-files.com/APIs/gRPC-API/index.md) > [Reference](https://developer.m-files.com/APIs/gRPC-API/Reference/index.md) > [Enums](https://developer.m-files.com/APIs/gRPC-API/Reference/Enums/index.md)

HTML version: https://developer.m-files.com/APIs/gRPC-API/Reference/Enums/MFiles.ExtAppEngine/

ScriptAppEngine enumeration.

- **Full name:** `MFiles.ExtAppEngine`
- **Proto file:** [`mfiles/enums.proto`](https://developer.m-files.com/APIs/gRPC-API/downloads/proto/mfiles/enums.proto)

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## Values

| Name | Number | Description |
|---|---|---|
| <a id="v-EXT_APP_ENGINE_UNKNOWN"></a>`EXT_APP_ENGINE_UNKNOWN` | 0 | Unknown. |
| <a id="v-EXT_APP_ENGINE_SHELL_UI"></a>`EXT_APP_ENGINE_SHELL_UI` | 1 | The Shell UI engine. |
| <a id="v-EXT_APP_ENGINE_VAULT_UI"></a>`EXT_APP_ENGINE_VAULT_UI` | 2 | The Vault UI engine. |
| <a id="v-EXT_APP_ENGINE_VAULT_CORE"></a>`EXT_APP_ENGINE_VAULT_CORE` | 3 | The Vault Core engine. |

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## Used in fields

- [`ExtAppModuleDef.script_engine`](https://developer.m-files.com/APIs/gRPC-API/Reference/Messages/MFiles.ExtAppModuleDef/index.md#f-script_engine): The script engine that can run this module.