SSO (single-sign-on) services, such as those provided by Facebook, Google and Microsoft Azure, are integrated into tens of millions of websites and cloud services, just like lock manufacturers offering locks for every home. Imagine you are a website developer, typically unfamiliar with SSO protocols. Your manager wants you to integrate a particular SSO service into a website written in a particular language (e.g., PHP, ASP.NET or Python). You are likely overwhelmed by the amount of work for finding a suitable SSO library, understanding its programming guide, and writing your code. Moreover, studies have shown that many SSO integrations on real-world websites are incorrect, and thus vulnerable to security attacks! SVAuth is an open-source project that tries to provide integration solutions for all major SSO services in all major web languages. Its correctness is ensured by a technology called self-verifying execution, which performs program verification at runtime. SVAuth is so easy to adopt that a website developer does not need any knowledge about SSO protocols or implementations. This paper describes the architecture of SVAuth and how to use it on real-world websites.