Open protocols help define interfaces. Project acceptance still depends on the functions and versions actually implemented.
Understand the OCPP boundary.
Open Charge Point Protocol governs communications between charging stations and charging management systems. The Open Charge Alliance describes versions 1.6, 2.0.1 and 2.1, with differing capabilities. Do not treat them as interchangeable.
Separate vehicle and backend interfaces.
Vehicle-to-charger communication, charger-to-management communication, roaming and payment are different interfaces. Specify the required use cases, implementation versions, security settings and test evidence for each.
Procure portability, not just a label.
Ask how configuration, tariffs, identities, operational records and certificates move if the management provider changes. Check contractual access to data and the practical migration process. Certification scope must match the relevant product and version.
Verify advanced functions end to end.
Smart charging and bidirectional functionality depend on compatible implementations and permissions throughout the system. This website explains the questions; it does not certify products or connect to chargers.