IndexedDB

The Indexed Database API, or IndexedDB (formerly WebSimpleDB), is a W3C recommended web browser standard interface for a transactional local database of JSON objects collections with indices. W3C issued its final recommendation for the IndexedDB interface on January 8, 2015.

Preliminary support for IndexedDB is included by Firefox (since version 4), Google Chrome (since version 11), and by Internet Explorer 10 Consumer Preview and Metro style apps. Apple announced support in Safari 8 for both iOS 8 and OS X at their WWDC 2014 Keynote on June 2, 2014.

Safari, Chrome 4, and Opera support an alternative mechanism for client-side database storage called Web SQL Database. On November 18, 2010, the W3C announced that the Web SQL database specification has reached an impasse and is no longer being actively worked on. Firefox developers have publicly stated that the lack of WebSQL Database support in Firefox is on purpose, as they believe it is a problematic standard which requires an alternative (hence IndexedDB).

IndexedDB can be used for browser implemented functions, such as bookmarks, as well as web applications, such as email. An open-source reference implementation of the Indexed Database API exists for testing and experimentation purposes. It has been used in eLibri a Library and eBook reader application.

IndexedDB is a transactional database embedded in the browser. The database is organised around the concept of collections of JSON objects similarly to NoSQL databases MongoDB or CouchDB. Each object is identified with a key generated during insert. An indexing system optimizes access to stored objects.

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