Chargy Mobile App

Chargy is a transparency software for secure and transparent e-mobility charging processes, as defined by the German "Eichrecht". The software allows you to verify the cryptographic signatures of energy measurements within charge detail records and comes with a couple of useful extentions to simplify the entire process for endusers and operators.

Chargy was inspired by TRuDI an Open Source Software project for transparency of smart meters.

You can find the app within the following app stores:

• Google PlayStore: Chargy Transparenz Software

Benefits of Chargy

1. Chargy comes with meta data. True charging transparency is more than just signed smart meter values. Chargy allows you to group multiple signed smart meter values to entire charging sessions and to add additional meta data like EVSE information, geo coordinates, tariffs, ... within your backend in order to improve the user experience for the ev drivers.
2. Chargy is secure. Chargy implements a public key infrastructure for managing certificates of smart meters, EVSEs, charging stations, charging station operators and e-mobility providers. By this the ev driver will always retrieve the correct public key to verify a charging process automatically and without complicated manual lookups in external databases.
3. Chargy is platform agnostic. The entire software is available for desktop and smart phone operating systems and .NET. If you want ports to other platforms or programming languages, we will support your efforts.
4. Chargy is Open Source. In contrast to other vendors in e-mobility, we belief that true transparency is only trustworthy if the entire process and the required software is open and reusable under a fair copyleft license (AGPL).
5. Chargy is open for your contributions. We currently support adapters for the protocols of different charging station vendors like chargeIT mobility, ABL (OCMF), chargepoint. The certification at the Physikalisch-Technische Bundesanstalt (PTB) is provided by chargeIT mobility. If you want to add your protocol or a protocol adapter feel free to read the contributor license agreement and to send us a pull request.
6. Chargy is white label. If you are a supporter of the Chargy project you can even use the entire software project under the free Apache 2.0 license. This allows you to create proprietary forks implementing your own corporate design or to include Chargy as a library within your existing application (This limitation was introduced to avoid discussions with too many black sheeps in the e-mobility market. We are sorry...).
7. Chargy is accessible. For public sector bodies Chargy fully supports the EU directive 2016/2102 on the accessibility of websites and mobile applications and provides a context-sensitive feedback-mechanism and methods for dispute resolution.

Supported Charge Transparency Data Formats

Currently supported formats include:

• Alfen charge transparency data
• Bauer energy meter data (2 format variants)
• ChargePoint transparency data (2 format variants)
• EDL40 and ISA-EDL40 SML data
• EMH energy meter data
• Mennekes XML
• OCMF, versions v1.1 to v1.4
  • Bonner Eichrechtstage Tariff Text Extensions
  • EdDSA support: Ed25519 and Ed448
  • Post-Quantum Cryptography support: ML-DSA-44, ML-DSA-65, ML-DSA-87
• Porsche Charging Data Format (PCDF)

Supported representations include:

• Plain Files containing a single charge transparency data set.
• chargeIT Container Format, a JSON-based container format for a single charging session (2 format variants).
• Chargy Container Format, a JSON-based container format for multiple charging sessions.
• SAFE XML Container Format, an XML-based container format for a single charging session, optionally enriched with additional Chargy metadata about the charging session.
• PTB Container Format, a JSON-based container format for a single charging session.
• Archive formats such as tar, ZIP, tar.gz, and similar formats that combine or compress multiple charge transparency files.
• QR-Code images, such as PNG, JPG, JPEG or SVG files, where the QR-Code represents a charge transparency data set.
• PDF/A-3 files transporting a charge transparency file as an embedded additional data stream.
• Charge Transparency Live Links, a JSON-LD document describing a charging session that is still running: where its live data can be fetched, the public keys to verify it with, and the signed meter values measured so far. See Charge Transparency Live Links below.

Charge Transparency Live Links

A charge transparency record describes a charging session that has finished. A charge transparency live link describes one that is still running: it carries what is already known — the station, the meter, the public keys, the signed meter values measured so far — and says where the next version of itself can be fetched.

The mobile app reloads such a document while the session runs. Because the document comes from outside and may name any URL at all, four gates decide what is actually fetched:

• The scheme: only https and wss, and only hosts on the public internet. No document, setting or user decision widens this; only a test bench build does (CHARGY_ALLOW_INSECURE_TRANSPORTS=1, see src/ts/buildFlags.ts).
• externalURLs.conf: an origin listed in this optional file next to index.html is polled without asking anyone, and so is the installation's own origin.
• The user, for everything else: asked once per origin and remembered — trust on first use, revocable in the settings, expiring after six months without use. The remembered decisions are stored the way OpenSSH stores a hashed known_hosts: salted hashes rather than the origins themselves, so a copy of the store does not reveal where its owner charges.
• The WebView's Content-Security-Policy, which bounds the hosts the page may reach at all.

The polling period is what the document asks for, clamped: no faster than every 5 seconds, no slower than once a day, and 10 seconds when the document does not say. Answers are size-capped, redirects are refused, and a transport may state HTTP headers to send with every request — a literal value, or a one-time password computed per request with @open-charging-cloud/totp.

The document format, what operators must provide (including the CORS preflight custom headers require), and what a client may do with these URLs are documented in Charge Transparency Live.

Building from Source

Chargy Mobile is an Apache Cordova application for Android and iOS. A browser target is available for development and testing.

For prerequisites, installation, tests, and regular browser or native builds, follow the build guide.

If a regular build fails because installed dependencies, generated web assets, Cordova platforms, or plugins are inconsistent, follow the rebuild and recovery guide.

Before release updates do not forget to:

npx cordova prepare android

Funding

This Open Source project is partially funded by the NGI Zero Commons Fund as part of our EVQI project.

We also appreciate any additional funding and long-term support for the Chargy family, for example via GitHub Sponsors, as it helps us keep the project sustainable, independent and useful for the entire e-mobility community.