# Variables
***
Flowise allow users to create variables that can be used in the nodes. Variables can be Static or Runtime.
### Static
Static variable will be saved with the value specified, and retrieved as it is.
### Runtime
Value of the variable will be fetched from **.env** file using `process.env`
### Override or setting variable through API
In order to override variable value, user must explicitly enable it from the top right button:
**Settings** -> **Configuration** -> **Security** tab:
If there is an existing variable created, variable value provided in the API will override the existing value.
```json
{
"question": "hello",
"overrideConfig": {
"vars": {
"var": "some-override-value"
}
}
}
```
### Using Variables
Variables can be used by the nodes in Flowise. For instance, a variable named **`character`** is created:
We can then use this variable as **`$vars.`** in the Function of the following nodes:
* [Custom Tool](https://docs.flowiseai.com/integrations/langchain/tools/custom-tool)
* [Custom Function](https://docs.flowiseai.com/integrations/utilities/custom-js-function)
* [Custom Loader](https://docs.flowiseai.com/integrations/langchain/document-loaders/custom-document-loader)
* [If Else](https://docs.flowiseai.com/integrations/utilities/if-else)
* Custom MCP
Besides, user can also use the variable in text input of any node with the following format:
**`{{$vars.}}`**
For example, in Agent System Message:
In Prompt Template:
## Resources
* [Pass Variables to Function](https://docs.flowiseai.com/integrations/langchain/tools/custom-tool#pass-variables-to-function)
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