Aptoide filed a lawsuit against Google in San Francisco federal court. The rival Android app store accuses Google of monopolizing app distribution and billing.
The suit alleges Google's practices block rival stores from accessing users and developers. Aptoide seeks an injunction and triple damages.
This challenge increases antitrust pressure on Alphabet. The company faces previous disputes over search and app-store policies.
Aptoide claims status as the world's third-largest Android app store. The company previously filed an EU antitrust complaint against Google in 2014.