Connect your chargers with Node.js

How a roaming charge flows

Sajilo Charge driver       Sajilo Charge hub                 Your Node.js backend
      │ taps "Start" ────▶ POST /commands/START_SESSION ──▶ onStartSession(charge)
      │                                                      your CSMS starts the charger
      │   charging…   ◀── PUT  sessions push ◀───────────── setActive() / meter(kwh)
      │ taps "Stop"  ────▶ POST /commands/STOP_SESSION ───▶ onStopSession(charge)
      │ wallet debited ◀── POST cdrs ◀──────────────────────  complete(kwh, cost)
      │                    monthly netting ─────────────────▶ you get paid

1.Install the SDK

One download, one package-manager command.

npm install https://sajilocharge.com/static/downloads/sajilocharge-ocpi-node.zip

2.Configure and mount

Tell the SDK who you are and where your server is publicly reachable. This mounts the three /ocpi endpoints the hub calls on you — everything else is outbound from your side.

const express = require('express');
const { createSajiloCharge } = require('sajilocharge-ocpi');

const sc = createSajiloCharge({
  partyId: 'ABC',                        // your 3-char party id
  countryCode: 'NP',
  name: 'ABC Charging Pvt. Ltd.',
  baseUrl: 'https://csms.example.com',   // public URL of this app
  storePath: './sajilocharge-ocpi.json',
  handlers,                              // written in the next step
});

const app = express();
app.use('/ocpi', sc.router);
app.listen(3000);

3.Wire your two charger callbacks

Every remote-start request becomes a RoamingCharge handed to your code. You implement exactly two methods; keep them fast and do the charger work asynchronously.

const handlers = {
  async onStartSession(charge) {
    // charge.locationId / charge.evseUid say which charger
    await myCsms.remoteStart(charge.evseUid, { ref: charge.id });
    return true;   // accepted; do the real work async
  },
  async onStopSession(charge) {
    await myCsms.remoteStop({ ref: charge.id });
    return true;
  },
};

4.Drive the charge lifecycle

From your CSMS events, three calls push the matching OCPI Session objects — and the final CDR that bills the driver — to the hub. The CDR is idempotent: it goes out exactly once per charge.

const charge = sc.charges.get(ref);
await charge.setActive();               // energy started flowing
await charge.meter(4.2);                // periodic session kWh
await charge.complete(18.5, 462.50);    // NPR; issues the CDR

5.Join the network

Request a one-shot registration token from partners@sajilocharge.com. Deploy first — the hub calls your /ocpi endpoints back during the handshake — then run the join. Tokens rotate on every re-registration; the registration token dies on first use.

# create sajilocharge.config.json with the same fields, then:
npx sajilocharge-ocpi join --token <registration-token>
npx sajilocharge-ocpi status      # → Status: ACTIVE

6.Publish your stations

Locations upsert by id — re-push whenever anything changes, keep live EVSE status fresh, and (optionally) verify drivers in real time for RFID or local starts.

await sc.client.pushLocation({
  id: 'LOC-KTM-01',
  name: 'ABC Hub Thamel',
  address: 'Thamel Marg 12',
  city: 'Kathmandu',
  coordinates: { latitude: '27.7154', longitude: '85.3123' },
  publish: true,
  evses: [{ uid: 'EVSE-01', status: 'AVAILABLE',
            connectors: [{ id: '1', standard: 'IEC_62196_T2',
                           format: 'SOCKET', power_type: 'AC_3_PHASE' }] }],
});

// live availability + optional driver check
await sc.client.updateEvse('LOC-KTM-01', 'EVSE-01', { status: 'CHARGING' });
await sc.client.authorize(tokenUid);  // ALLOWED | NO_CREDIT | BLOCKED

Money and settlement

• All amounts are NPR; costs are VAT-exclusive.
• Each CDR credits your inter-party ledger at the hub; settlement is monthly netting minus the hub clearing fee.
• Disputes: the hub's CDR dispute endpoint or partners@sajilocharge.com — open disputes pause netting for that CDR.

Troubleshooting

• Join fails with "could not fetch endpoints" — your base URL isn't publicly reachable, or the OCPI routes aren't mounted. The hub must be able to call you back during the handshake.
• 401 on hub calls — the connection was re-registered somewhere else; join again with a fresh registration token.
• Session push returns "No matching session" — push only charges the hub initiated, after START_SESSION was accepted.
• Rate limits — the hub throttles per-party (default 300 req/min); meter updates every 30–60 s are plenty.

Other stacks

Django (Django ≥ 4.2 · Python ≥ 3.10) · Laravel (Laravel 10 / 11 / 12 · PHP ≥ 8.1) · Spring Boot (Spring Boot 3.2+ · Java 17+)

Sajilo Charge Node.js SDK v0.1.0 · OCPI 2.2.1 · Questions: partners@sajilocharge.com