OCPP 1.6J is version 1.6 of the Open Charge Point Protocol — the language between a charger and its management platform — carried as JSON messages over a WebSocket connection. The “J” is the operative letter: OCPP 1.6 exists in two variants, and 1.6J names the JSON one, as opposed to the older SOAP/XML variant written 1.6S or just 1.5/1.6 SOAP. It is the version named most often on commercial charger spec sheets.
Key Takeaways
- OCPP 1.6J = protocol version 1.6, JSON transport, carried over a persistent WebSocket connection.
- The “J” distinguishes it from the SOAP/XML variant of the same version; charger and platform must match on version and variant.
- “OCPP-ready” is not 1.6J — it names no version, and a project should close it in writing.
- EVDANCE states 1.6J for the EV-AC03201T and EV-RHDC30K-L; the EV-ACS3210E states “OCPP-ready” — carry each claim exactly as written.
Why Version 1.6 Comes in Two Variants
OCPP began with SOAP, an XML-based messaging format inherited from enterprise software. Version 1.6 kept the same operations — starting and stopping sessions, reporting meter values, authorisation, status — and added a second way to carry them: JSON, a lighter text format, sent over a WebSocket, which is a single connection the charger opens to the platform and holds open for messages in both directions. Same conversation, two envelopes:
| OCPP 1.6 SOAP (1.6S) | OCPP 1.6J (JSON) | |
|---|---|---|
| Message format | XML in a SOAP envelope | JSON text |
| Connection style | Separate web-service requests | One persistent WebSocket the charger holds open |
| Where you still meet it | Older platforms and legacy networks | The default on current spec sheets and platforms |
| What the charger can do | The same 1.6 operations — the variant changes the transport, not the feature list | |
The plain definition of OCPP itself — what the protocol is and what travels over it — is set out in our article on how commercial charging stations work and the operator-level detail in our OCPP explainer for operators. This article stays on the four characters after the name: 1.6J.
Why the Letter Is the Checkable Part of the Claim
Interoperability is a match, not a badge. A charger and a platform connect when they run the same protocol version and the same transport variant — a 1.6J charger does not talk to a SOAP-only platform just because both say “1.6”. That is why spec sheets write the letter, and why a buyer should read it literally:
- “OCPP 1.6J” stated — a complete, testable claim: version 1.6, JSON transport. The remaining check is a tested pairing with your named platform.
- “OCPP 1.6” with no letter — an incomplete claim. Ask which variant before a project relies on it.
- “OCPP-ready” — a capability phrase naming no version at all. It is a different, weaker claim than 1.6J and must never be read as one; close the version and the tested platforms in writing.
- No OCPP claim — a standalone unit, however good its own app is. App control is not a platform connection.
The Claim on EVDANCE Listings
EVDANCE’s range shows the grades side by side. The EV-AC03201T dual-connector AC station (two Type 2 connectors, up to 43 kW shared, RFID, IP54) and the EV-RHDC30K-L compact DC charger (22 kW DC, IP54, LCD) state OCPP 1.6J. The EV-ACS3210E portable states “OCPP-ready” alongside its App and energy monitoring — the phrase only, with no version named. Those are three different statements, and a tender or site plan should carry each one exactly as written. One boundary: EVDANCE makes the hardware; the platform the charger reports to is a separate service, run by its own provider, and the pairing is what a project confirms — in writing, before the hardware ships.
Frequently Asked Questions
Is OCPP 1.6J the newest version?
No — a later version, OCPP 2.0.1, exists. Newer is not automatically better for a project: what decides is whether the charger and the platform you run share a version and variant. 1.6J remains the most widely named pairing in commercial hardware.
Does 1.6J make a charger “smart”?
It makes it manageable: a platform can run sessions, billing records and fault reporting through it. Which features a driver or operator actually sees depends on the platform and the site’s setup, not on the protocol string alone.
My platform supports OCPP 1.6. Will any 1.6 charger join it?
Only if the variant matches — 1.6J to a JSON platform, 1.6 SOAP to a SOAP one — and the specific pairing has been tested. Ask both sides for the tested combination, in writing, before purchase.
Related Reading
- OCPP Explained: What Charge Point Operators Need From EV Charger Hardware
- How Do Commercial EV Charging Stations Work?
- How Do Smart EV Chargers Work?
