go-ocpp - Open Charge Point Protocol Client and Server Library for Go

A pure Go implementation of the Open Charge Point Protocol, for both roles: the Charging Station (OCPP 1.6: Charge Point) and the CSMS (OCPP 1.6: Central System). Both share one RPC engine, and either side can send requests once connected.

Status: Phase 7 of 8 (hardening). OCPP 1.6J (with the Security Whitepaper extensions), OCPP 2.0.1 and OCPP 2.1 are complete at the message level: every action is typed, validated against the OCA schemas, and dispatchable in both roles; 2.1 adds the SEND and CALLRESULTERROR message types. 1.6J and 2.0.1 pass against five independent implementations, 2.1 against three (two CSMSs, The Mobility House and CitrineOS, and the EVerest libocpp station), including TLS and compression (ocpp-interop v0.4.1). See IMPLEMENTATION_PLAN.md.

Docs: Architecture · Requirements · Specifications · Plan · API (client, server) · Errors · Observability · Security · Interoperability · Compatibility · Features and gaps · Releases

• Protocol versions
• Install
• Quick start
• Interoperability
• Assurance
• Development
• License

go get github.com/otfabric/go-ocpp

Requires Go 1.26 or later. The only dependency of the library is coder/websocket (ADR 0002); the tests also use a reference JSON Schema validator (ADR 0003).

A CSMS and a charging station, OCPP 2.0.1 (the examples run complete, self-contained versions of this for 1.6 and 2.0.1):

// CSMS: answer the stations' CALLs.
type csms struct{ ocpp201.UnimplementedCSMSHandler }

func (csms) BootNotification(ctx context.Context, p ocpp.Peer, req *ocpp201.BootNotificationRequest) (*ocpp201.BootNotificationResponse, error) {
    return &ocpp201.BootNotificationResponse{Status: ocpp201.RegistrationStatusAccepted, CurrentTime: time.Now().UTC(), Interval: 300}, nil
}

srv, err := server.New(
    server.WithHandler(ocpp.V201, ocpp201.CSMS(csms{})),
    server.WithAuthenticator(server.BasicAuth(lookupPassword)),
)
http.Handle("/ocpp/", srv) // behind TLS

// Send a CALL to a connected station.
if s, ok := srv.Station("STATION001"); ok {
    resp, err := ocpp201.Reset(ctx, s, &ocpp201.ResetRequest{Type: ocpp201.ResetOnIdle})
}

// Charging station.
c, err := client.New("wss://csms.example.com/ocpp/STATION001",
    client.WithHandler(ocpp.V201, ocpp201.ChargingStation(station{})),
    client.WithBasicAuth("STATION001", password),
    client.WithReconnect(client.DefaultReconnect()),
    client.WithCompression(),
)
err = c.Connect(ctx)
boot, err := ocpp201.BootNotification(ctx, c, &ocpp201.BootNotificationRequest{
    Reason:          ocpp201.BootReasonPowerUp,
    ChargingStation: ocpp201.ChargingStationType{VendorName: "OTFabric", Model: "TestStation"},
})

Every request is validated against its schema before it is sent, every response when it arrives, and every incoming request before a handler sees it; an invalid one is answered with the CALLERROR its violation calls for.

go-ocpp is a protocol library. It transports, validates and dispatches messages. Charging behaviour, authorization policy, persistence and billing belong to the application's handlers.

go-ocpp is tested in both roles against The Mobility House ocpp 2.1.0 (1.6J, 2.0.1, 2.1), ChargeTimeEU Java-OCA-OCPP v2.0 and lorenzodonini/ocpp-go v0.19.0 (1.6J, 2.0.1), as a CSMS against EVerest libocpp (1.6J, 2.0.1, 2.1), and as a station against CitrineOS core v2.0.1 (1.6J, 2.0.1, 2.1), as packaged by otfabric/ocpp-interop v0.4.1: every action, security profiles 1 to 3 and compression. 1458 scenarios pass and none fails; the skipped ones are documented upstream defects and capabilities a reference does not have, and every payload the references send passes go-ocpp's schema validation. See INTEROPERABILITY.md and the per-version matrices in docs/compatibility.

make interop   # needs Docker

go-ocpp distinguishes three levels of assurance and claims only the first two, once tests establish them:

make help     # list targets
make check    # format, lint, vet, vuln, test, coverage, cross-build

See CONTRIBUTING.md and AGENTS.md.

MIT; see LICENSE. OCPP specifications and schemas are © Open Charge Alliance, licensed under CC BY-ND 4.0, and are not part of this licence. See SPECIFICATIONS.md.