# python: declare_var
URL: https://generaltranslation.com/en-US/docs/python/api/declare-var.mdx
---
title: declare_var
description: API reference for the declare_var function
---

## Overview

`declare_var` wraps a dynamic value with a GT variable marker so that translation engines can preserve the variable in translated output.

```python
from gt_flask import declare_var  # or from gt_fastapi import declare_var

greeting = declare_var("Alice", name="user")
```

## Reference

### Parameters

<TypeTable
  type={{
    "variable": {
      type: 'str | int | float | bool | None',
      description: 'The value to embed as a non-translatable variable.',
    },
    "name?": {
      type: 'str',
      optional: true,
      description: 'Optional human-readable variable name.',
    },
  }}
/>

### Returns

`str` — an ICU select construct that wraps the value as a GT variable marker.

---

## Notes

- Use `declare_var` for values that change at runtime (e.g., user names, counts).
- See also [`declare_static`](/docs/python/api/declare-static) for values known at build time.
- Use [`decode_vars`](/docs/python/api/decode-vars) to extract the variables back from a marked string.