---title: Valtiodescription: This doc describes Valtio extension.nav: 4.98keywords: valtio,proxypublished: false---
Jotai's state resides in React, but sometimes it would be niceto interact with the world outside React.
Valtio provides a proxy interface that can be used to store some valuesand sync with atoms in Jotai.
This only uses the vanilla api of valtio.
### Install
You have to install `valtio` and `jotai-valtio` to use this feature.
```npm i valtio jotai-valtio```
## atomWithProxy
`atomWithProxy` creates a new atom with valtio proxy.It's two-way binding and you can change the value from both ends.
```jsximport { useAtom } from 'jotai'import { atomWithProxy } from 'jotai-valtio'import { proxy } from 'valtio/vanilla'
const proxyState = proxy({ count: 0 })const stateAtom = atomWithProxy(proxyState)const Counter = () => { const [state, setState] = useAtom(stateAtom) return ( <> count: {state.count} <button onClick={() => setState((prev) => ({ ...prev, count: prev.count + 1 }))} > inc atom </button> <button onClick={() => { ++proxyState.count }} > inc proxy </button> </> )}```
### Parameters
```atomWithProxy(proxyObject, options?)```
**proxyObject** (required): the Valtio proxy object you want to derive the atom from
**options.sync** (optional): makes the atom update synchronously instead of waiting for batched updates, similar to [`valtio/useSnapshot`](https://github.com/pmndrs/valtio#update-synchronously). This will result in more renders, but have more guarantees that it syncs with other Jotai atoms.
```atomWithProxy(proxyObject, { sync: true })```
### Examples
<CodeSandbox id="ew98ll" />## mutableAtom
`mutableAtom` wraps a value in a self-aware Valtio proxy. You can make changes to it in the same way you would to a normal js-object.
Count value is stored under the `value` property.
```jsxconst countProxyAtom = mutableAtom(0)
function IncrementButton() { const countProxy = useAtomValue(countProxyAtom) return <button onClick={() => ++countProxy.value}>+</button>}```
### Parameters
```jsmutableAtom(value, options?)```
**value** (required): the value to proxy.
**options.proxyFn** (optional): allows customization with `proxyFn` for custom proxy functions. Can be `proxy` (default) or a custom function.
### Examples
<CodeSandbox id="f84sk5" />### Caution on Mutating Proxies
Be careful to not mutate the proxy directly in the atom's read function or during render. Doing so could cause an infinite render loop.
```tsconst countProxyAtom = mutableAtom(0)
atom( (get) => { const countProxy = get(countProxyAtom) ++countProxy.value // This will cause an infinite loop }, (get, set) => { const countProxy = get(countProxyAtom) ++countProxy.value // This is fine },)```