A confluence of maturing Web technologies and Web platforms affords a new form of scientific communication: free and open nowcasting of public opinion. Here, I present the first open-source system to do so. The automated system gathers new human responses to survey items daily, anonymizes and publicly distributes microdata, and presents analyses through a publicly viewable Web dashboard. A demonstration implementation tracked support for further development of artificial intelligence at daily resolution. As of 2024-11-17, the system had autonomously produced 214 daily estimates of support. I argue that more scientists should adopt the method of open nowcasting, because it encourages transparency in research design and eases replication.