Starting 29 March 2018, Google opened the first stage of registration for .app domains, which means that domain names under that extension can be registered from that date.
On 14 May 2015, ICANN and Charleston Road Registry Inc. (CRI), entered into a Registry Agreement under which CRI (Sponsoring Organization owned by Google), will operates the .app top-level domain.
Besides, Google decided to apply for new top-level domains (TLDs) after ICANN decided to expand the overall number of generic TLDs, reason why Google bought the .app domain for 25 million and became the administrative contact.