In short: OCPP is the open protocol that lets a charger talk to back-office software from any supplier. Buying chargers that support it, and proving that support through certification, means you can change software provider without replacing hardware. Today OCPP 1.6 is still widely used, OCPP 2.0.1 is the international standard, and OCPP 2.1 adds bidirectional charging and energy management. Ask suppliers which version they support, whether it is certified, and how easily you can switch.
For a buyer, the most important thing about charger software is often not its features but whether you can leave it. OCPP is what makes that possible. This guide explains what it is, the versions in use and what to put in a specification.
What is OCPP?
The Open Charge Point Protocol is a free, open standard for communication between a charger and a central management system, often called the back office or CPMS. It is maintained by the Open Charge Alliance. Through OCPP, the back office can start and stop sessions, authorise drivers, read meter values, set charging limits, receive fault alerts and update firmware.
Without it, chargers and software from the same supplier are locked together. With it, you can choose hardware and software separately and change either later.
Which versions are in use?
| Version | Released | What to know |
|---|---|---|
| OCPP 1.6 | 2015 | Still common in existing estates. Mature and well understood, but with weaker security and device management than later versions. |
| OCPP 2.0.1 | 2020 | Better security, device management and smart charging. Approved as international standard IEC 63584 in 2024. |
| OCPP 2.1 | January 2025 | Builds on 2.0.1 and adds bidirectional charging (V2X) and control of distributed energy resources. |
The dates are from the Open Charge Alliance’s protocol page, which also makes an important point: OCPP 1.6 and OCPP 2.0.1 are not compatible. A charger running one cannot talk to a back office that only supports the other. By contrast, the Alliance says application logic built for 2.0.1 remains compatible with 2.1.
Which version should you ask for?
For new purchases, ask for OCPP 2.0.1 at least, with a clear path to 2.1 by firmware update if you may want bidirectional charging or close integration with on-site energy systems. Accept 1.6 only where the rest of your estate and back office depend on it, and ask the supplier how and when the charger can be upgraded.
Check the back office side as well. There is no benefit in 2.0.1 chargers if your chosen software only speaks 1.6.
How do you know support is real?
“OCPP compatible” can mean anything from a full implementation to a partial one with proprietary extras. Ask for certification. The Open Charge Alliance runs an OCPP certification programme with independent testing laboratories. Ask which profiles the charger is certified for, then check the certificate.
Also ask for a list of back-office systems the charger has been integrated with in live service, and contact one of those customers.
What else should the specification cover?
- Smart charging: the back office must be able to set power limits per charger and per site, which is the basis of load management.
- Security: encrypted communication and secure firmware updates.
- Data ownership: you should own session and fault data and be able to export it.
- Switching: a contractual commitment that chargers can be pointed at another OCPP back office, with no fee or remote lock.
- Proprietary features: list any functions that only work with the supplier’s own software, so you know what you would lose by switching.
Our guide to writing a charger tender shows how to fit these into a full specification.
How does OCPP relate to OCPI and ISO 15118?
They are often confused, but they connect different parties.
| Protocol | Connects | Used for |
|---|---|---|
| OCPP | Charger and back office | Operating and managing chargers |
| OCPI | Charge point operators and mobility service providers | Roaming: drivers using one app or card across networks |
| ISO 15118 | Vehicle and charger | Plug & Charge, smart charging and bidirectional power |
OCPI is maintained by the EVRoaming Foundation, which describes it as supporting connections between e-mobility service providers and charge point operators. ISO 15118 is what enables Plug & Charge, where the vehicle and charger handle identification and billing automatically, without a card or app.
Frequently asked questions
Can an OCPP 1.6 charger be upgraded to 2.0.1?
Sometimes, by firmware update, if the hardware supports it. Ask the manufacturer for a written commitment and timeline before you buy.
Does OCPP matter for a small depot?
Yes. Even a few chargers may outlast the software contract, and OCPP lets you change provider without replacing hardware.
Is OCPP enough to avoid lock-in?
It is the foundation, but contracts matter too. Make sure you own your data and can switch back office without fees or remote restrictions.
Our procurement and supplier selection service checks OCPP claims and integration track records before you commit. Ask us about your shortlist.
