SondeHub grew from a May 2018 joke domain that redirected radiosonde hunters to Habhub into an open platform for tracking weather-balloon transmitters, publishing data, and predicting balloon paths. Its operators began proxying radiosonde data in 2018 as Habhub struggled with the volume of daily launches, then built compatible APIs, a prediction service, live feeds, and an S3 data archive. A reverse-prediction feature uses wind models and a balloon’s observed path to estimate launch locations, identifying poorly documented launch sites and, according to its operator, some military installations and vessels. The platform has drawn attention from government, military, aviation, and accident-investigation organizations. SondeHub received a 2021 request to remove a sensitive military installation from maps and says it removes launch-site data after genuine requests. During the February 2023 balloon incidents, traffic rose after SondeHub was linked by The Washington Post; its operator says the US allegedly used an AIM-9X missile against an amateur radio balloon. In late 2024, repeated prediction API requests from an AWS IP were traced to users connected with Ukrainian military groups using wind predictions for balloon and fixed-wing operations. SondeHub asked AWS not to block the account, provided instructions for locally running its predictor, and cited concerns that an interruption could risk lives. The US NTSB contacted SondeHub in September 2025 while investigating balloons near Utah; Windborne later said one of its balloons likely collided with an aircraft and changed its system.