Website and app developers using the Google Maps APIs will have to start paying if their products use more than 25,000 map loads per day.
Google announced the changes in a blog post on Wednesday, delivering on a decision made in April. It had said that it would begin limiting API access from 1 October.
"We understand that the introduction of these limits may be concerning. However with the continued growth in adoption of the Maps API we need to secure its long term future by ensuring that even when used by the highest volume for-profit sites, the service remains viable," Thor Mitchell, product manager of Google Maps API, wrote.
"By introducing these limits we are ensuring that Google can continue to offer the Maps API for free to the vast majority of developers for many years to come," Mitchell added.
Users exceeding the 25,000 map loads per API, per day limit — or 2,500 if using the customised 'Styled' maps feature — will not stop working immediately but will have to either reduce their usage, pay the excess usage fees or purchase an Maps API premier license.
In order to help customers assess usage, Google is also adding the Maps API to the API console. Excess loads will be sold through the console and are priced at $4 per 25,000 for the standard version of the maps. Excess usage is calculated daily and billed monthly, Google said.
Google will begin charging for excess loads from "early 2012" but said it will provide at least 30 days' notice before it starts billing customers.