“Technology companies are increasingly experimenting with “warrant canaries” as a means of increasing transparency around the national security orders they receive. A warrant canary is a statement that a company regularly publishes, declaring that the company has never received a national security order. Should the company stop publishing the statement, the public can infer that the company has received such an order. This paper explores the constitutional and practical implications raised by this practice. It examines the various types of canaries that companies have used thus far, and proposes best practices for companies going forward. It also argues that canaries are protected by the First Amendment, and that any order compelling a company to publish a false canary must survive strict scrutiny, if not an even more exacting standard of review. Ultimately, this paper advocates for a company committed to transparency to adopt and litigate a test canary to establish that canaries can be lawful tools.”