If you operate, or plan to operate, a network of EV chargers, OCPP is the protocol that decides which hardware you can buy, which software you can run it on, and how much control you retain over your own network. This guide covers what OCPP actually is, how it works, and what it does - and doesn't - solve for an enterprise charge point operator (CPO).
What OCPP Is
The Open Charge Point Protocol (OCPP) is an open communication standard, maintained by the Open Charge Alliance, that lets EV charging stations (“charge points”) talk to a central management system (a CSMS - Charging Station Management System) over a network connection. Before OCPP existed, every charger manufacturer shipped its own proprietary management software, which meant an operator buying hardware from two vendors effectively had to run two separate back-office systems.
OCPP breaks that dependency. Any charger that implements OCPP correctly can, in principle, connect to any OCPP-compliant CSMS - regardless of who manufactured the hardware or who built the software. That's the entire point of the standard: it turns the charger-to-software relationship from a proprietary lock-in into an interoperable one.
How OCPP Works
A charge point opens a persistent connection to a CSMS - historically over SOAP, and in modern deployments almost always JSON over WebSocket - and the two sides exchange structured messages for things like:
- Boot and status notifications - the charger announcing itself and reporting connector state (available, occupied, faulted).
- Authorization - checking whether an RFID card, app tap or ad-hoc payment is allowed to start a session.
- Transaction events - starting a session, streaming meter values during charging, and stopping the session.
- Remote commands - the CSMS telling a charger to start, stop, reset, or update its firmware.
- Smart charging profiles - the CSMS instructing a charger to limit or shape its power draw.
This message exchange is what makes a modern CSMS possible: it's the layer underneath station management, live monitoring, remote commands and smart charging.
OCPP 1.6 vs. OCPP 2.0.1
Two versions dominate real-world deployments today: OCPP 1.6 (specifically the JSON variant, OCPP 1.6J) and OCPP 2.0.1. They are not backward compatible at the message level, which is the single biggest operational fact to understand before you commit to hardware or a migration timeline - covered in full in OCPP 1.6 vs. OCPP 2.0.1: A Migration Guide for Charge Point Operators.
What OCPP Does Not Cover
This is where most first-time buyers get surprised. OCPP standardizes the charger-to-CSMS conversation - it says nothing about tariffs and pricing logic, payment processing, invoicing, driver-facing mobile apps, customer accounts, roaming between networks, or business reporting. A charger that “speaks OCPP” gives you connectivity, not a charging business.
Roaming - letting a driver from one network charge on another operator's stations - is handled by a separate, complementary standard, OCPI (Open Charge Point Interface), not by OCPP itself.
OCPP and White-Label Charging Platforms
Because OCPP is hardware-agnostic by design, it's also what makes a white-label EV charging platform practical: a platform built on open OCPP support isn't tied to one charger manufacturer, so an operator can source hardware from whoever fits their sites and budget, and run all of it - alongside tariffs, billing, and a branded driver app - under a single account. CarChargeOS's platform layer supports OCPP 1.6J, 2.0.1, 2.0.1 Ed3 and 2.1 for exactly this reason: it keeps the hardware decision separate from the software decision.
Frequently asked questions
Do I need OCPP if I'm only running a handful of chargers?
Technically no - some very small deployments run on vendor-proprietary systems. But any charger bought without OCPP support becomes a long-term liability the moment you want to add a second hardware vendor, switch software providers, or scale past a single site.
Is OCPP the same as OCPI?
No. OCPP governs the connection between a charger and its management system. OCPI governs roaming between different charging networks - letting a driver authenticated on one platform charge on another operator's stations.
Can a single CSMS support chargers on both OCPP 1.6 and 2.0.1 at the same time?
Yes, and this matters in practice - most operators grow their network in phases and end up with a mixed fleet. A platform with multi-vendor, multi-version OCPP support can manage both generations of hardware from one back office without forcing an all-at-once hardware refresh.
Who maintains the OCPP standard?
The Open Charge Alliance (OCA), a consortium of charging hardware manufacturers, CSMS providers and industry stakeholders, publishes and maintains the OCPP specification.