Privacy Policy.

Particle HSC, a sole trader business based in New South Wales, Australia. Contact for anything in this policy: particlehsc@gmail.com.

Account details you give us:

• Your email address, a username, your year (Year 11 or Year 12), the subjects you study (Physics and or Chemistry), and an optional nickname.
• Your password, which is stored hashed by our authentication provider. We never see it.
• If you sign in with Google, Google sends us the email address and name on your Google account.
• We do not ask for your school, full name, phone number, address or date of birth.

Study data created as you use Particle:

• The answers you type, and photos of handwritten answers you upload.
• The marks, breakdowns and feedback you receive, which questions you attempted, how long you took, how the marker classified any lost marks, and any re-marks.
• What you tell us in the app: skip reasons, diagnostic and readiness ratings, the exams you add (dates, modules, the mark you type in afterwards, your notes), saved questions and collections, thumbs up or down on questions, and feedback or contributions you send.

Payment and technical data:

• If you subscribe, Stripe collects your card details directly. We receive a Stripe customer reference, the subscription status and the email used to pay. We never see or store your full card number.
• Server logs record the IP address and browser type of requests for security and rate limiting, kept briefly.
• A secure cookie keeps you signed in; your theme preference is stored in your browser. We use no advertising or tracking cookies.

• To run the service: sign you in, mark your answers, show your history, progress and analytics, and choose which questions to serve you next.
• To show a leaderboard, which displays usernames and counts of questions practised only.
• To take payment for Unlimited and manage your subscription.
• To answer support requests and act on feedback.
• To keep the service secure, enforce the one-device rule and fair-use limits, and detect automated or abusive use.
• To improve the marking and the question bank, using answers in de-identified form (for example, auditing a sample of marks against real marking guidelines).
• To meet legal obligations, such as keeping payment records.

We do not sell personal information, and we do not use it for advertising.

To mark a written answer, we send the question and your answer (the text you typed or the photo you uploaded) to Anthropic, the provider of the Claude models, which processes it in the United States. Nothing that identifies you is sent with it: no name, email or account details. Under the terms we use Anthropic on, your content is not used to train their models. Multiple-choice answers are checked on our own server and never sent to any AI provider.

Keep your answers to your Physics or Chemistry working. Do not type your own or anyone else's personal information into an answer, and crop photos to the working itself.

• Supabase: our database and sign-in provider, which stores your account and study data.
• Vercel: hosts the website, in its Sydney, Australia region.
• Anthropic: marks written answers, in the United States, as described in section 4.
• Stripe: processes payments and stores card details under its own privacy policy.
• Resend: delivers the emails we send you, such as password resets.
• Google: only if you choose to sign in with Google.

Each of these providers acts on our instructions to deliver the service. Some of them store or process data outside Australia, including in the United States. We choose providers with established security practices, and we do not otherwise disclose your information unless the law requires it.

Your username and the number of questions you have practised can appear on the leaderboard. No other user can see your answers, marks, email, year or exams. You can change your username at any time in Settings.

• All traffic to and from Particle is encrypted (HTTPS).
• Passwords are hashed. The keys that access the database and the marking provider never leave our servers.
• One signed-in device at a time. Signing in elsewhere signs the previous device out.
• Access to production data is limited to what is needed to operate the service and handle support.

No system is perfectly secure. If we become aware of a breach that is likely to cause you serious harm, we will notify you and the Office of the Australian Information Commissioner as the law requires.

• Your account and study data: for as long as your account exists.
• When you ask us to delete your account, we delete your account and study data within 30 days.
• Payment records: Stripe and we keep the records the law requires (in Australia, generally seven years for tax purposes). They do not include your card number.
• Server logs: deleted on a rolling basis, generally within weeks.

Particle is built for Year 11 and Year 12 students. You must be at least 13 to create an account, and we do not knowingly collect information from anyone younger. If you are under 18, a parent or guardian may contact us at any time to ask what we hold about your account, to correct it, or to have it deleted, and we will act on that request once we have confirmed who they are.

You can ask us at any time to:

• tell you what personal information we hold about you and give you a copy;
• correct anything that is wrong;
• delete your account and the data attached to it.

Email particlehsc@gmail.com from the address on your account. We respond within 30 days and we do not charge for these requests. If you are unhappy with how we have handled your information or a request, tell us first and we will try to fix it. You can also complain to the Office of the Australian Information Commissioner at oaic.gov.au.

If we change how we handle your information, we will update this page and the date at the top, and for a significant change we will tell you by email or in the app before it takes effect.