OCPI (Open Charge Point Interface) is developed and maintained by the EVRoaming Foundation, a non-profit organization dedicated to facilitating EV charging interoperability. OCPI enables communication between different charging networks and other players such as payment providers, making it the backbone of EV charger data sharing services globally.

OCPI 2.2.1, released in 2020, has emerged as the dominant version of the protocol in operation today. This version standardizes how charging networks exchange critical information including location data, pricing, session details, and billing information. Its widespread adoption has been instrumental in breaking down the "walled gardens" of charging networks, allowing EV drivers to seamlessly charge across different operators using a single account or app.

The success of OCPI 2.2.1 can be attributed to its comprehensive feature set, which includes token validation, charge detail record exchange, real-time availability updates, and standardized tariff structures. These capabilities have made it possible for drivers to locate available chargers, start sessions, and pay for charging across network boundaries without needing multiple apps or RFID cards.

While newer versions are in development to address emerging needs like plug-and-charge authentication and smart charging coordination between networks, OCPI 2.2.1 (along with 2.1.1) remains the workhorse protocol that powers most cross-network charging experiences today. For charging network operators looking to expand their reach and provide a seamless experience for drivers, implementing OCPI 2.2.1 is currently the most practical path to joining the growing ecosystem of interoperable charging services.