Google Privacy Upgrades Could Jolt Gmail App Developers

Google’s plan to lower the risk of another privacy gaffe is likely to disrupt business for scores of app developers that build services using the wealth of data generated by the world’s most popular email service. The Alphabet unit said it is reining in the data it makes available to outside developers of Gmail apps as part of a broader effort to secure the privacy of its users. Apps that don’t fall into categories of either email or productivity services will be cut off from all Gmail data, and other developers will be restricted from selling data they collect or using it to target advertising or market research, Google said.

The rule changes, which take effect Jan 9, threaten to choke off the main source of revenue for a cluster of companies in the email data business. Hundreds of outside software developers scan the inboxes of millions of Gmail users who have signed up for email-based services in areas like finance, travel, and scheduling—and often collect information about these users’ buying habits and sell it to marketers. Google’s shift illustrates the tradeoffs tech giants face as they try to maintain an ecosystem of apps offering potentially attractive services and to ensure ironclad data protections for users.