Privacy

In effect from 21 September 2026

Who is responsible for your data

Will Percey, trading as Moonlight Software, a sole trader, is the controller of the personal data described here. Address: [address to be added]. Email: [contact email to be added].

This website

The site sets no cookies, uses no analytics or tracking, and makes no requests to other companies: its fonts and icons are served from the site itself. Our hosting provider may keep standard server logs (IP address, time, page requested, browser) for a short period to keep the site running and secure.

The web editor

The web editor runs entirely in your browser. Files you open stay on your computer, and diagrams are drawn in the browser. Your settings are kept in your browser's local storage, on your device. Nothing you write is sent to us.

One exception you control: the editor can be pointed at a PlantUML server of your choosing. If you set that up, your diagram source goes to that server, under whatever terms it has. It is off unless you turn it on.

The desktop app

The app keeps your files, boards, notes and history on your own computer. It connects out only for the following.

Licence checks

When you activate a licence key, the app sends the key and your computer's name to Lemon Squeezy. The name is there so you can tell your computers apart when moving a licence between them. After that, about once a day, the app sends the key and an identifier for this activation to confirm the subscription is still active. Your 30-day trial is tracked on your computer and nothing about it is sent anywhere.

Update checks

The app checks our website for new versions and downloads them from it. As with any web request, the server sees your IP address, which may appear in its logs.

Crash reports, only if you switch them on

Crash reporting is off by default. If you turn it on in Settings → Privacy, the app sends a report when something goes wrong to Sentry, a crash-reporting service, stored in its EU region. A report contains the error, where in Gnomon's code it happened, the app version, and your operating system and its version. Before anything is sent, the app removes file paths (which can reveal project and client names) and your computer's name, and it never attaches your diagrams or your identity. Turning the setting off stops reports.

Claude

Gnomon can work with Claude through your own Claude Code installation, on your computer. Anything a Claude session sends to Anthropic is between you and Anthropic, under your agreement with them. Gnomon sends nothing to Anthropic itself.

When you buy

Subscriptions are sold by Lemon Squeezy as merchant of record. It collects your payment details, processes payment, charges tax and sends receipts, under its own privacy policy. We never see your card. We receive your name, email address, country, and the details of your order, subscription and licence activations, which we use to provide your licence, support you, and keep the records the law requires.

When you email us

We use what you send us to answer you, and keep it for as long as that conversation needs.

Why we are allowed to use it

• To provide what you bought or asked for: licence checks, purchases and support.
• Our legitimate interests: update checks, and keeping the site and app secure.
• Your consent: crash reports, which you can withdraw at any time in Settings.
• Legal obligation: purchase records we must keep for tax.

How long we keep it

Purchase records are kept for as long as UK tax law requires, currently up to six years. Crash reports are deleted automatically by Sentry after its retention period. Support emails are kept for as long as the conversation needs, and then deleted.

Where it goes

Lemon Squeezy is based in the United States, and processing there is covered by appropriate safeguards under UK data protection law. Crash reports are stored in Sentry's EU region. We do not sell your data or share it with anyone else.

Your rights

You can ask us for a copy of your personal data, to correct it, to delete it, to restrict or object to how we use it, or to have it in a portable form. Email us and we will reply within a month. If you are unhappy with how we handle your data, you can complain to the Information Commissioner's Office at ico.org.uk.

Changes

If this policy changes in a way that matters, we will say so here and, where we can, tell you directly. The date at the top shows when the current version took effect.