Aspects discussed herein relate to providing alerts to a community of devices located in or near a geographic are such as a building or property. The alerts override any alert-inhibiting state of the mobile device to deliver audio, visual, and/or haptic alerts in emergency situations. The communication and emergency alert system may be used to communicate with many different communities of people. Moreover, certain individuals may be members of more than one community at the same time, and the communities themselves may change over time based both on the user's preferences and on their physical locations. A variety of application programming interfaces can be provided to allow third-party applications to generate, transmit, and display alerts that override any alert-inhibiting state of a mobile device.