Signal emerges as the go-to app for both Trump supporters and detractors.

The people helping Elon Musk try to cut federal bureaucracy and the activists working to stop them both use the same app: Signal, a secure communication app of choice. Signal was launched over a decade ago but is considered by mobile security experts as the gold standard of end-to-end encrypted messaging and calls. It is used not only by privacy-conscious activists but also by officials, lawmakers, military commanders and business executives. The app’s popularity rose before it made the news — when Trump aides accidentally copied in a reporter to a Signal conversation about Yemen airstrikes, thus proving its importance in Washington. Sensor Tower data shows that the app’s downloads in the U.S. increased by 16% in the first quarter of 2025 compared to the previous quarter, and by 25% year-on-year compared to the same period in 2024. In Washington, D.C., Signal is used by congressional aides and political appointees and is owned by the nonprofit Signal Foundation. To spice up a conversation, people say, “Let’s move this to Signal.” The AP found more than 1,100 government officials from all 50 states using it. The New York Times and the Wall Street Journal have reported that Musk’s Department of Government Efficiency is using Signal to implement its goal of cutting costs. He also used the app during his 2022 Twitter takeover and most recently chatted on Signal with Ashley St. Clair, a right-wing influencer and the mother of one of his children. Some governments go as far as promoting Signal. In 2020, the European Commission told staff to use it for public instant messaging. US officials have not gone that far, but the Cybersecurity and Infrastructure Security Agency issued guidance in late 2024 for senior leaders to use encrypted apps like Signal, indicating its growing use.