What is local storage? How does Facebook use local storage technologies?

Local storage is an industry-standard technology that allows a website or app to store and retrieve data on a person’s computer, mobile phone or other device. Some examples include device or HTML5 local storage and caching. Most web browsers offer settings for you to control whether or not to allow local storage.

We use local storage to understand and improve how our products and services perform and to enable certain features. For example, we may store certain parts of the Facebook website on your device so that those pages load faster the next time you visit them. Local storage also allows us to provide certain services to someone who doesn’t have access to the internet. For example, you can read and compose messages in the Facebook Messenger app when you’re offline because we store those messages locally on your device. We may also use local storage to help us understand how you use websites, apps and computers or mobile devices. For example, we may use local storage on your device in connection with things like apps, where we cannot use cookies.