Standards like OCPP and ISO 15118 describe how EV charging should work, yet real-world deployments often behave differently. This session explains why a full stack of tools, testing methods, and feedback loops is essential for true interoperability, and how the open-source EVerest ecosystem has become a practical integration point for these technologies. We will show how Software-in-the-Loop testing, Golden SUT validation, conformance tooling, virtual charger parks, testing-hackathons, and cloud-based remote debugging work together to close the gap between specification and reality. The talk demonstrates how open-source reference implementations can strengthen standards, improve certification tools, and reduce interoperability pain across the EV charging industry.