Privacy
What Epilykos does and does not do with your data, including backups to Google Drive.
Troubleshooting
Fixes for the problems people run into most.
Terms of service
The terms for using Epilykos, the software and this documentation.
Epilykos is software you run yourself, on your own box or server. The project does not run a service that your readings are sent to, has no user accounts, and receives none of your data.
Last updated: 13 November 2026.
What stays on your box
Your readings, history, settings, layouts, saved passwords and tokens are stored in a database on the device where you installed Epilykos. They are not sent to the Epilykos project or to anyone else unless you choose to connect a service, as described below.
Services you choose to connect
Epilykos talks to a service only when you set one up, and sends it only what that service needs. For example, your Solcast key and rooftop details go to Solcast for a forecast, a Telegram bot token goes to Telegram to send you a message, and your Home Assistant address and token go to your Home Assistant. Each of these is governed by that service's own privacy policy.
Epilykos also checks for new versions from the project's public update feed. That request carries no personal data from your box, though the host of the feed (GitHub) sees it as it would any web request.
The dashboard and settings pages load their fonts, scripts and styles from the box itself, and Epilykos includes no advertising or analytics trackers.
Backups to other places
Epilykos can send a backup of your database to a folder you choose, and, if you connect it, to your own Google Drive. The copy is locked on your box before it leaves: Epilykos encrypts the whole file with a passphrase you choose. The passphrase is not sent anywhere and is not part of the file, so the storage provider sees only encrypted data and the project cannot read it.
Google user data
This section applies only if you connect your Google account to back up to Google Drive. It is optional, and Epilykos works fully without it.
- What Epilykos asks for. Permission to see and manage only the files Epilykos itself creates in your Drive, in a folder called Epilykos. It does not ask to read your other files, your email, your contacts or your calendar, and it cannot see them.
- What it accesses. The encrypted backup files it created, and the Epilykos folder that holds them. It does not read your name, email address or any other profile detail.
- How it uses it. To upload an encrypted backup, to list the backups in that folder so you can choose one to restore, to download the one you choose, and to delete older backups so only the number you chose is kept. It does nothing else with your Google account.
- Where it is stored. The sign-in token Google gives your box is stored on your own box, locked with the box's own key. The backup files are stored in your own Google Drive. The project has no server and receives neither.
- Sharing. Information from your Google account is not shared with, sold to or given to anyone, and the project does not receive it.
- Advertising and AI. It is not used for advertising, profiling, or to develop or train any generalised AI or machine-learning model.
- Human access. Nobody at the project can read your Google data, because it never reaches us. The backup files are encrypted, so even someone with access to your Drive sees only unreadable data.
- How long it is kept. The sign-in token stays on your box until you disconnect Google Drive or delete the box. Backup files stay in your Drive until Epilykos replaces them with newer ones, or you delete them.
- Stopping and deleting. Switch remote backup off in Settings → Backup and restore to stop all uploads. To withdraw Epilykos's access to your Google account, remove it at myaccount.google.com/permissions, then delete the Epilykos folder in Drive if you no longer want the copies.
Epilykos's use and transfer to any other app of information received from Google APIs will adhere to the Google API Services User Data Policy, including the Limited Use requirements.
Your control
You can export or delete your data at any time. A backup file is the whole database, and deleting the database or uninstalling Epilykos removes everything it holds. Nothing is retained by the project, because the project never receives it.
Contact and changes
Questions about privacy can be raised as an issue on the Epilykos project on GitHub. If this page changes, the date above changes with it. The rules for using Epilykos are in the Terms of service.
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