source
Beginning on June 11, 2018, you’ll need to enable billing with a
credit card and have a valid API key for all projects. This will give
you the ability to scale easily with less downtime and fewer
performance issues. In addition, we’re simplifying our 18 individual
APIs into three products: Maps, Routes, and Places.
Also, in June 2016 we announced that we would stop supporting keyless
usage, meaning any request that doesn’t include an API key or Client
ID. This will go into effect on June 11th, and keyless access will no
longer be supported. At that time, keyless calls to the Maps
JavaScript API and Street View API will return low-resolution maps
watermarked with “for development purposes only.” Keyless calls to any
of the following APIs will return an error: Maps Static API (including
Static Street View), Directions API, Distance Matrix API, Geocoding
API, Geolocation API, Places API, Roads API, and Time Zone API.
To avoid a service interruption to your projects, please visit our Get
Started page to enable a billing account and generate an API key. Once
you generate and secure an API key, make sure to update your
application with the new API key.