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---title: Persistencedescription: How to persist atomsnav: 7.14---
Jotai has an [atomWithStorage function in the utils bundle](../utilities/storage.mdx) for persistence that supports persisting state in `sessionStorage`, `localStorage`, `AsyncStorage`, or the URL hash.
(Note: This guide is a bit outdated and requires some rewrites.)
There are also several alternate implementations here:
### A simple pattern with localStorage
```jsconst strAtom = atom(localStorage.getItem('myKey') ?? 'foo')
const strAtomWithPersistence = atom(  (get) => get(strAtom),  (get, set, newStr) => {    set(strAtom, newStr)    localStorage.setItem('myKey', newStr)  },)```
### A helper function with localStorage and JSON parse
```jsconst atomWithLocalStorage = (key, initialValue) => {  const getInitialValue = () => {    const item = localStorage.getItem(key)    if (item !== null) {      return JSON.parse(item)    }    return initialValue  }  const baseAtom = atom(getInitialValue())  const derivedAtom = atom(    (get) => get(baseAtom),    (get, set, update) => {      const nextValue =        typeof update === 'function' ? update(get(baseAtom)) : update      set(baseAtom, nextValue)      localStorage.setItem(key, JSON.stringify(nextValue))    },  )  return derivedAtom}```
(Error handling should be added.)
### A helper function with AsyncStorage and JSON parse
This requires [onMount](../core/atom.mdx#onmount-property).
```jsconst atomWithAsyncStorage = (key, initialValue) => {  const baseAtom = atom(initialValue)  baseAtom.onMount = (setValue) => {    ;(async () => {      const item = await AsyncStorage.getItem(key)      setValue(JSON.parse(item))    })()  }  const derivedAtom = atom(    (get) => get(baseAtom),    (get, set, update) => {      const nextValue =        typeof update === 'function' ? update(get(baseAtom)) : update      set(baseAtom, nextValue)      AsyncStorage.setItem(key, JSON.stringify(nextValue))    },  )  return derivedAtom}```
Don't forget to check out the [Async documentation](../guides/async.mdx) for more details on how to use async atoms.
### Example with sessionStorage
Same as AsyncStorage, just use `atomWithStorage` util and override the default storage with the `sessionStorage`
```jsimport { atomWithStorage, createJSONStorage } from 'jotai/utils'
const storage = createJSONStorage(() => sessionStorage)const someAtom = atomWithStorage('some-key', someInitialValue, storage)```
### A serialize atom pattern
```tsxtype Actions =  | { type: 'serialize'; callback: (value: string) => void }  | { type: 'deserialize'; value: string }const serializeAtom = atom(null, (get, set, action: Actions) => {  if (action.type === 'serialize') {    const obj = {      todos: get(todosAtom).map(get),    }    action.callback(JSON.stringify(obj))  } else if (action.type === 'deserialize') {    const obj = JSON.parse(action.value)    // needs error handling and type checking    set(      todosAtom,      obj.todos.map((todo: Todo) => atom(todo)),    )  }})
const Persist = () => {  const [, dispatch] = useAtom(serializeAtom)  const save = () => {    dispatch({      type: 'serialize',      callback: (value) => {        localStorage.setItem('serializedTodos', value)      },    })  }  const load = () => {    const value = localStorage.getItem('serializedTodos')    if (value) {      dispatch({ type: 'deserialize', value })    }  }  return (    <div>      <button onClick={save}>Save to localStorage</button>      <button onClick={load}>Load from localStorage</button>    </div>  )}```
#### Examples
<Stackblitz id="vitejs-vite-zda5uw" file="src%2FApp.tsx" />### A pattern with atomFamily
```tsxtype Actions =  | { type: 'serialize'; callback: (value: string) => void }  | { type: 'deserialize'; value: string }const serializeAtom = atom(null, (get, set, action: Actions) => {  if (action.type === 'serialize') {    const todos = get(todosAtom)    const todoMap: Record<string, { title: string; completed: boolean }> = {}    todos.forEach((id) => {      todoMap[id] = get(todoAtomFamily({ id }))    })    const obj = {      todos,      todoMap,      filter: get(filterAtom),    }    action.callback(JSON.stringify(obj))  } else if (action.type === 'deserialize') {    const obj = JSON.parse(action.value)    // needs error handling and type checking    set(filterAtom, obj.filter)    obj.todos.forEach((id: string) => {      const todo = obj.todoMap[id]      set(todoAtomFamily({ id, ...todo }), todo)    })    set(todosAtom, obj.todos)  }})
const Persist = () => {  const [, dispatch] = useAtom(serializeAtom)  const save = () => {    dispatch({      type: 'serialize',      callback: (value) => {        localStorage.setItem('serializedTodos', value)      },    })  }  const load = () => {    const value = localStorage.getItem('serializedTodos')    if (value) {      dispatch({ type: 'deserialize', value })    }  }  return (    <div>      <button onClick={save}>Save to localStorage</button>      <button onClick={load}>Load from localStorage</button>    </div>  )}```
#### Examples
<Stackblitz id="vitejs-vite-z4kjv3" file="src%2FApp.tsx" />