Privacy & Cookie Notice
Last updated: April 2026 · ARCH (browser application)
1. Overview
ARCH is a local-first application: your diagrams and projects are processed and stored in your web browser. We do not operate a login system or a central database of your diagrams on our servers for core editor functionality.
2. What we store on your device
- IndexedDB — project snapshots, workspace data, and related editor state so your work persists between visits.
- localStorage / sessionStorage — UI preferences (e.g. theme), consent flags, dismissals, and similar settings.
- Service worker cache (after first load in production) — static assets so the app can load faster or when offline; no personal data is required for that cache beyond what the browser already stores.
3. Cookies & analytics
We do not use cookies for cross-site advertising profiles. Any first-party storage (including technologies treated similarly to cookies under EU law) is used for essential operation of the site: functionality, security of your session in the browser, and remembering your choices (such as this consent).
On each visit we load Analytics to collect aggregated usage statistics (e.g. which pages are viewed, device or browser type). The underlying service processes that data under its own terms as a processor; we do not use it for cross-site advertising profiles. The cookie banner's Accept & continue only records that you have seen our notice and dismisses the bar; it does not turn analytics on or off. You may use browser extensions, ad blockers, or similar tools where available to limit analytics collection.
4. Legal bases (GDPR / UK GDPR)
Where EU or UK law applies, we rely on Article 6(1)(b) (steps prior to or performance of a contract / provision of the service you request) for essential local processing. For Analytics, we rely on Article 6(1)(f) (legitimate interests) in measuring how our site and app are used, balanced against your rights, and—where required—on Article 6(1)(a) (consent) for storing your banner dismissal preference in local storage.
5. Your rights
Because data stays on your device, you can export your work (e.g. .arch bundles where available) and clear site data for this origin in your browser settings to erase local copies. You may also have rights to access, rectification, erasure, restriction, objection, and portability under applicable law — for data held only in your browser, exercising these rights is often done through your browser or by deleting data as above. For analytics data held by the analytics provider, you may also use tools that provider or your browser offers, where applicable.
6. Third parties & links
The app may link to external sites (documentation, support, etc.). Those sites have their own policies. We do not control them.
7. Changes
We may update this notice when the product changes. The "Last updated" date at the top will change when we do.
8. Contact
For privacy questions about ARCH, contact the operator of the site where this app is hosted (e.g. via the contact or social links published on the landing page).