Building a Smart EV Charging App

Building a Smart EV Charging App with Oracle APEX PWA and REST Integration

Why I Built This App

As more people in my neighborhood switch to electric vehicles, I wanted to offer a simple and fair way for them to charge their EVs at my private charging station—and pay only for what they actually use. Instead of manually calculating consumption, prices, and sharing bank details, I decided to build an app that automates everything.

The result: a lightweight, modern Oracle APEX Progressive Web App (PWA) that gives full transparency into charging sessions and pricing—built to be used by friends, family, and neighbors.

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Key Features

1. Installable Progressive Web App (PWA)

The app can be installed like a native app on Android or iOS. Thanks to APEX’s native support for PWA manifests and service workers, it works offline and loads fast.

2. Easy Input for Charging Sessions

Users simply enter:

Start and End Meter Readings

Charging Start/End Date and Time

From that, the app automatically calculates:

kWh Charged

Amount to Pay

Price per kWh (excluding tax)

3. Real-Time Price Calculation with Dynamic Actions

No need to refresh the page or click a submit button. Using APEX Dynamic Actions, the app:

Instantly reacts to user inputs

Calculates costs based on live pricing

Applies logic like fixed fees, markup, and taxes

This creates a smooth and interactive user experience

4. Live Spot Market Price Integration

Electricity prices vary throughout the day. To reflect this, a REST Background Process syncs hourly with live spot market data. APEX Scheduler + REST Data Sources make it possible to:

Fetch hourly electricity prices

Store them in a backend table

Use them in cost calculations

5. Transparent Price Breakdown

Users see a breakdown:

Energy Used (kWh)

Total Price to Pay (€)

Base Cost (without tax and fees)

Additional cost logic includes:

8 cent price fee

10 cent fixed "TomFee"

20% VAT

6. Interactive Chart for Price Visualization

A simple bar chart shows hourly spot prices, helping users understand when the charging was cheapest or most expensive. It uses the built-in APEX charting engine for fast rendering and tooltips.

7. Support & Appreciation

Two buttons allow neighbors to show their appreciation:

PayPal Tom

Buy me a Coffee

These buttons use direct links to external services and are integrated using standard APEX button actions.

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Tech Stack

Oracle APEX 23.x

PWA (Manifest + Service Worker)

REST Data Source + APEX Scheduler

JavaScript Dynamic Actions

APEX Charts for UI Visualization

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What I Learned

APEX Dynamic Actions are perfect for real-time calculations.

REST + Scheduler makes it easy to stay in sync with external APIs.

PWAs make it easier for casual users (like neighbors!) to use the app without installing anything from an app store.

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Final Thoughts

This app isn’t just a tech demo—it’s a practical solution for real-world sharing. It helps me provide a neighborhood charging station where everyone can see exactly what they used and what they owe. Transparent, fair, and easy.

If you’re working on similar projects or want to support the idea, you know where the coffee button is!