Senior Backend Engineer, EV Charging Platform (OCPP / IoT) - PT - Worldwide

About the project

Client is an Australian startup building an EV charging platform for hotels, motels and short-stay accommodation. Guests book, download client's app, pre-authorize payment, then start charging by entering their mobile number on the charger keypad. You'll build the cloud backend that talks directly to the chargers, manages charging sessions and handles split payments between properties and the client.

What you'll build

• An OCPP 1.6J central system (JSON over secure WebSockets), designed for a clean migration path to OCPP 2.0.1
• Charger authentication and session control: validating the guest's phone number against their booking window and payment status, then starting and stopping transactions remotely
• Resilient session handling over cellular connections: reconciling MeterValues after a dropped connection, with no duplicate sessions or billing errors
• Booking-window logic: activation at check-in time, expiry at 23:59 on checkout day, and automatic remote StopTransaction after that
• A pay-as-you-go billing engine: live kWh and tariff tracking, a Stripe Connect split between the property and rEVflux, and idempotent payment retries
• Xero accounting integration

Requirements

• 5+ years of backend development in Node.js (TypeScript) or Go
• Hands-on OCPP experience: you've built or extended a CSMS (charge point management system) and connected real chargers
• Strong PostgreSQL skills, including transactions, row-level locking and ledger-style data integrity
• Redis for session state and caching
• Stripe Connect or similar marketplace or split-payment integrations
• Experience building fault-tolerant, idempotent systems such as payments or IoT
• Comfortable owning architecture decisions and explaining trade-offs to non-technical founders

Nice to have

• OCPP 2.0.1 experience
• Experience with specific EV charger brands or firmware
• Xero API integration
• Experience in the Australian energy or EV market