OCMF

Open Charge Metering Format: the common container for signed meter readings of a charging session, with gateway, meter, identification, readings and signature, kept by SAFE e.V.

Explained in

Payments and billing · Deep diveThe signed meter values of one sessionThe commuter's 38.20 kWh as the charger's meter signed them: one OCMF dataset with gateway, meter, identification, two readings and the signature, and the public key that verifies it.

Where measuring law asks for it, as in Germany, the meter signs its readings so that a driver can check them later (stop 06). The common container for that is OCMF, the Open Charge Metering Format, kept by SAFE e.V. and used by meters and charge controllers across manufacturers: a JSON section with gateway, meter, identification and readings, followed by the signature. OCPP carries the dataset from the charger to the backend, OCPI passes it on to the provider, and the invoice links to it.

From “What you are looking at”, stop 09
  1. OCPPOpen Charge Point Protocol: the open protocol between a charger and its operator's backend.
  2. OCPIOpen Charge Point Interface: an open protocol for roaming between operators and e-mobility service providers.
  1. Open Charge Alliance: Signed Meter Values (Eichrecht paper), version 1.0, February 2025. https://openchargealliance.org/wp-content/uploads/2025/05/signed_meter_values-v10-1.pdf. Checked 09 Oct 2026. Licence: CC BY-ND 4.0.
  2. SAFE e.V.: OCMF, Open Charge Metering Format: specification on GitHub. https://github.com/SAFE-eV/OCMF-Open-Charge-Metering-Format. Checked 11 Oct 2026.
  3. Open Charge Alliance: Signed Meter Values (Eichrecht paper), version 1.0, February 2025. https://openchargealliance.org/wp-content/uploads/2025/05/signed_meter_values-v10-1.pdf. Checked 09 Oct 2026. Licence: CC BY-ND 4.0.