# useCookie > useCookie is an SSR-friendly composable to read and write cookies. ## Usage Within your pages, components, and plugins, you can use `useCookie` to read and write cookies in an SSR-friendly way. ```ts const cookie = useCookie(name, options) ``` `useCookie` only works in the [Nuxt context](/docs/4.x/guide/going-further/nuxt-app#the-nuxt-context). The returned ref will automatically serialize and deserialize cookie values to JSON. ## Type ```ts [Signature] import type { Ref } from 'vue' import type { CookieParseOptions, CookieSerializeOptions } from 'cookie-es' export interface CookieOptions extends Omit { decode?(value: string): T encode?(value: T): string default?: () => T | Ref watch?: boolean | 'shallow' readonly?: boolean refresh?: boolean } export interface CookieRef extends Ref {} export function useCookie ( name: string, options?: CookieOptions, ): CookieRef ``` ## Parameters `name`: The name of the cookie. `options`: Options to control cookie behavior. The object can have the following properties: Most of the options will be directly passed to the [cookie](https://github.com/jshttp/cookie) package.
Property Type Default Description
decode (value: string) => T decodeURIComponent + destr . Custom function to decode the cookie value. Since the value of a cookie has a limited character set (and must be a simple string), this function can be used to decode a previously encoded cookie value into a JavaScript string or other object.
Note: If an error is thrown from this function, the original, non-decoded cookie value will be returned as the cookie's value.
encode (value: T) => string JSON.stringify + encodeURIComponent Custom function to encode the cookie value. Since the value of a cookie has a limited character set (and must be a simple string), this function can be used to encode a value into a string suited for a cookie's value.
default () => T | Ref undefined Function returning the default value if the cookie does not exist. The function can also return a Ref .
watch boolean | 'shallow' true Whether to watch for changes and update the cookie. true for deep watch, 'shallow' for shallow watch, i.e. data changes for only top level properties, false to disable.
Note: Refresh useCookie values manually when a cookie has changed with refreshCookie .
refresh boolean false If true , the cookie expiration will be refreshed on every explicit write (e.g. cookie.value = cookie.value ), even if the value itself hasn’t changed. Note: the expiration is not refreshed automatically — you must assign to .value to trigger it.
readonly boolean false If true , disables writing to the cookie.
maxAge number undefined Max age in seconds for the cookie, i.e. the value for the Max-Age Set-Cookie attribute . The given number will be converted to an integer by rounding down. By default, no maximum age is set.
expires Date undefined Expiration date for the cookie. By default, no expiration is set. Most clients will consider this a "non-persistent cookie" and will delete it on a condition like exiting a web browser application.
Note: The cookie storage model specification states that if both expires and maxAge is set, then maxAge takes precedence, but not all clients may obey this, so if both are set, they should point to the same date and time!
If neither of expires and maxAge is set, the cookie will be session-only and removed when the user closes their browser.
httpOnly boolean false Sets the HttpOnly attribute.
Note: Be careful when setting this to true , as compliant clients will not allow client-side JavaScript to see the cookie in document.cookie .
secure boolean false Sets the Secure Set-Cookie attribute .
Note: Be careful when setting this to true , as compliant clients will not send the cookie back to the server in the future if the browser does not have an HTTPS connection. This can lead to hydration errors.
partitioned boolean false Sets the Partitioned Set-Cookie attribute .
Note: This is an attribute that has not yet been fully standardized, and may change in the future.
This also means many clients may ignore this attribute until they understand it.
More information can be found in the proposal .
domain string undefined Sets the Domain Set-Cookie attribute . By default, no domain is set, and most clients will consider applying the cookie only to the current domain.
path string '/' Sets the Path Set-Cookie attribute . By default, the path is considered the "default path" .
sameSite boolean | string undefined Sets the SameSite Set-Cookie attribute .
- true will set the SameSite attribute to Strict for strict same-site enforcement.
- false will not set the SameSite attribute.
- 'lax' will set the SameSite attribute to Lax for lax same-site enforcement.
- 'none' will set the SameSite attribute to None for an explicit cross-site cookie.
- 'strict' will set the SameSite attribute to Strict for strict same-site enforcement.
## Return Values Returns a Vue `Ref` representing the cookie value. Updating the ref will update the cookie (unless `readonly` is set). The ref is SSR-friendly and will work on both client and server. ## Examples ### Basic Usage The example below creates a cookie called `counter`. If the cookie doesn't exist, it is initially set to a random value. Whenever we update the `counter` variable, the cookie will be updated accordingly. ```vue [app/app.vue] ``` ### Readonly Cookies ```vue ``` ### Writable Cookies ```vue ``` ### Refreshing Cookies ```vue ``` ### Cookies in API Routes You can use `getCookie` and `setCookie` from [`h3`](https://github.com/h3js/h3) package to set cookies in server API routes. ```ts [server/api/counter.ts] export default defineEventHandler((event) => { // Read counter cookie let counter = getCookie(event, 'counter') || 0 // Increase counter cookie by 1 setCookie(event, 'counter', ++counter) // Send JSON response return { counter } }) ``` --- - [Source](https://github.com/nuxt/nuxt/blob/main/packages/nuxt/src/app/composables/cookie.ts)