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Privacy Notice

Last updated: 17 October 2026

This notice explains how Stefan Lago, trading as Abstraction Systems (Untersiggenthal, Switzerland), collects and uses personal data through SketchAlchemy. We are the controller for the personal data described below.

Data we collect

  • Account data: name, email address, and authentication identifiers (via Google sign-in or email/password), managed through Firebase Authentication.
  • Content you upload: the images you convert, the images and Excalidraw scenes we generate from them, and your conversion history.
  • Usage data: conversions performed, token/cost telemetry, and technical logs (e.g. IP address, device/browser information) generated as part of running the Service.
  • Blog comments and reactions: if you comment on a blog post, the comment text, the name you choose to show with it, and when you posted it; if you like or dislike a post, that reaction, linked to your account.
  • Support messages: anything you send us at our support address.
  • Payment data: collected and processed directly by Paddle (see below) — we don't receive or store your card details.

Why we collect it

We process this data to:

  • create and secure your account, and authenticate you (performance of a contract);
  • run conversions and store your history so you can access past results (performance of a contract);
  • detect abuse, prevent fraud, and keep the Service secure (legitimate interest);
  • respond to support requests (performance of a contract / legitimate interest);
  • publish your blog comments and count reactions, and moderate them (performance of a contract / legitimate interest);
  • meet billing, tax, and legal obligations, largely fulfilled by Paddle as an independent controller of your payment data (legal obligation).

Who we share it with

We share personal data only where needed to run the Service:

  • Google Cloud / Firebase — hosting, authentication, database, and file storage.
  • Google Gemini API — processes the images you submit to generate the cleaned image and Excalidraw scene.
  • Google Analytics (via Firebase) — only if you've consented to analytics (see Cookies & analytics below); measures site usage and marketing campaign performance. See Google's privacy policy.
  • Paddle (Paddle.com) — our merchant of record for subscriptions, one-time purchases, tax, and invoicing. Paddle acts as an independent controller for the payment data it collects from you; see Paddle's own privacy notice.
  • Professional advisers (e.g. accountant) where needed, and authorities where required by law or to protect rights and safety.

We don't sell your personal data.

International transfers

Our infrastructure providers (Google Cloud/Firebase, Google Gemini API, Paddle) process data on servers located outside Switzerland, including in the United States and the European Union. Where required, we rely on standard contractual clauses or equivalent safeguards offered by these providers.

Data retention

We keep your account and conversion history for as long as your account is active, so you can access past conversions. If you delete your account, we delete or anonymize your personal data within a reasonable period, except where we must keep records for legal, tax, or billing purposes.

Blog comments are public. The comment and the name you chose are visible to anyone reading the post, and may be read by search engines. Your email address is never shown, and like and dislike reactions are never shown individually (only the total number of likes is public). You can delete your own comments at any time; we may hide or remove comments that are spam, abusive, or off-topic. Comments and reactions are deleted together with your account, or earlier on request.

Your rights

Depending on where you live, you may have the right to access, correct, delete, or export your personal data, object to certain processing, or withdraw consent. To exercise any of these, contact us at the address below. If you're in the EU/EEA or UK, you also have the right to lodge a complaint with your local data protection authority.

Cookies & analytics

We use essential cookies/local storage needed to keep you signed in and remember your preferences (e.g. light/dark mode). These are required for the Service to work and aren't optional.

With your consent, we also use Google Analytics (via Firebase) to understand how visitors find and use SketchAlchemy, and to measure how specific marketing campaigns (e.g. a paid ad) perform. Analytics is off by default: nothing loads and no analytics data is sent until you accept it via the consent banner or the "Privacy settings" link available on every page, and you can withdraw consent at the same place at any time. If you choose "Accept all", we additionally allow Google Ads conversion measurement: Google may set an advertising cookie so that a signup or purchase can be attributed to the Google ad you clicked. "Analytics only" leaves this off. We don't use remarketing, ad personalization, or Google Signals, and we don't build cross-site advertising profiles.

If you arrive via a marketing link carrying campaign parameters (for example "utm_source"), and you've consented to analytics, we store that campaign information locally in your browser for up to 30 days. If you create an account within that window, it's attached once to your account so we can measure which campaigns lead to signups and paying customers — it's never attached retroactively to an existing account, and it's a separate figure from Google Analytics' own session-attribution numbers, which won't exactly match it.

Security

We use industry-standard technical and organizational measures — including encryption in transit and access controls — to protect your data, provided through our infrastructure providers.

Changes to this notice

We may update this notice from time to time; the date at the top reflects the latest revision.

Contact

For any privacy question or request, contact us at support@sketchalchemy.io.