Privacy Policy

1. Who are we?

Vocabingo is a multilingual vocabulary learning app based on spaced repetition, published on a personal basis by an individual (see the Contact page for full legal details). The data controller is the publisher of the Service.

2. Data collected and purposes

2.1 Via Clerk (authentication)

When you create an account, Clerk, Inc. collects and stores your email address, a hashed password (or an OAuth token if you use a third-party provider), your unique Clerk identifier (userId), and creation/login timestamps. This data is stored on Clerk's infrastructure in the United States, covered by the EU Standard Contractual Clauses (SCCs).

Purpose: authentication and session management. Legal basis: Art. 6(1)(b) GDPR – performance of a contract (access to the Service).

2.2 In our PostgreSQL database

For signed-in users, we store in our own database:

• Learning history: word identifier, review stage (6 levels), date learned, next review date, outcome (remembered or forgotten). Linked to your Clerk userId.
• Daily statistics: number of words learned, reviewed, remembered, and forgotten per day.
• Current session state: progress of an interrupted session (words processed, current index), retained for 24 hours to allow resumption.

This data is pseudonymised: only the Clerk userId (an opaque string) appears - no name or email address. Purpose: provision of the spaced-repetition service. Legal basis: Art. 6(1)(b) GDPR.

2.3 Via PostHog (usage analytics)

We use PostHog to measure usage of the Service (page views, user journeys, session completion rates). PostHog receives your pseudonymised Clerk identifier (userId), visited URLs, and functional events (e.g. word learned, review completed). No personally identifiable data (name, email) is sent to PostHog.

Data is hosted on PostHog's European infrastructure (eu.i.posthog.com). Purpose: Service improvement and error detection. Legal basis: Art. 6(1)(a) GDPR – consent (opt-in via cookie banner).

2.4 Via Stripe (payments)

For users subscribed to the Pro plan, payments are processed by Stripe Inc. / Stripe Payments Europe Ltd. Payment data (card number, billing address) is processed directly by Stripe and never passes through our servers. We receive only a Stripe customer and subscription identifier, and the subscription status (active, cancelled, etc.). Purpose: payment processing and subscription management. Legal basis: Art. 6(1)(b) GDPR – performance of a contract. Stripe's privacy policy: stripe.com/privacy.

2.5 Local storage (localStorage)

One preference is stored locally in your browser: soundEnabled (whether sound effects are on). This boolean value is never sent to our servers and does not constitute personal data.

2.6 Guest users

No data is saved server-side for guest sessions. Progress is lost when the tab is closed.

3. What we do not do

• No advertising or ad targeting.
• No sale or sharing of your data with third parties for commercial purposes.
• No third-party advertising trackers (no Google Analytics, Segment, Mixpanel, remarketing pixels, etc.).
• No remarketing pixels.
• Card data never passes through our servers (processed exclusively via Stripe).

4. Cookies

The Service uses strictly necessary cookies:

These cookies are strictly necessary for the operation of the Service (authentication) and secure payment processing. They do not require prior consent under Article 5(3) of the ePrivacy Directive.

5. Data retention

Your learning data is retained for as long as your Clerk account is active. It is automatically deleted shortly after your Clerk account is deleted, or immediately upon explicit request from the Settings.

Temporary session data (enabling session resumption) is automatically deleted after 24 hours of inactivity.

6. Your rights (GDPR)

In accordance with Regulation (EU) 2016/679 (GDPR), you have the following rights:

• Right of access (Art. 15) - you can download all your learning data in JSON format from the Settings.
• Right to rectification (Art. 16) - your identity information (email, name) can be updated in your Clerk account settings.
• Right to erasure (Art. 17) - you can delete all your learning data from the Settings.
• Right to data portability (Art. 20) - JSON export available from the Settings.
• Right to object (Art. 21) - you can stop using the Service and delete your account at any time.
• Right to lodge a complaint - you may contact your national data protection authority. In France: www.cnil.fr.

To exercise your rights other than through the interface, contact us via the Contact.

7. International transfers

Clerk, Inc. is based in the United States. The transfer of identity data to Clerk is governed by the Standard Contractual Clauses (SCCs) adopted by the European Commission, in accordance with Art. 46 GDPR.

Our learning data is hosted on secure cloud infrastructure. Data may transit through servers in the United States or the EU. Our host is a signatory to the EU–US Data Privacy Framework.

PostHog (PostHog Inc.) – Anonymised usage analytics. Analytics data is hosted in Europe (eu.i.posthog.com) and no personally identifiable data is transmitted. Privacy policy: posthog.com/privacy.

Stripe (Stripe Inc. / Stripe Payments Europe Ltd.) – Card payment processing. Payment data is processed directly by Stripe and never passes through our servers. Stripe Payments Europe Ltd. is based in Ireland (EU); Stripe Inc. is based in the United States and covered by the Standard Contractual Clauses. Privacy policy: stripe.com/privacy.

8. Withdrawing consent

You can withdraw your consent to analytics cookies at any time by clicking "Withdraw analytics cookie consent" in the Settings. Navigation data collected before withdrawal will not be deleted automatically - contact us via the Contact.

9. Changes to this policy

We may update this policy at any time. The last-updated date at the top of the page will be revised accordingly. For substantial changes affecting your rights, registered users will be notified by email.

10. Anonymous proficiency-test data

This section covers a distinct processing activity: the free vocabulary proficiency test at /test, which anyone can take without registering. Your responses and, if you opt in, your email address are processed separately from any Vocabingo account you may hold.

10.1 What we collect

When you take the test we store: the language and UI locale you chose; the exact form you were served (item order, versioned scoring identifier); your yes/no responses; the scored result (estimated CEFR level, vocabulary size range, confidence indicators); the date of your sitting; and a keyed hash of your IP address (never the raw IP). If you separately opt into the email report we additionally store: the email address you supplied; a one-time verification token; the timestamp at which you clicked the verification link; the version identifier of the consent text you agreed to; and whether you also opted into marketing updates.

10.2 Lawful basis

The email report and any optional marketing updates rely on your explicit consent under Article 6(1)(a) GDPR. Consent is asked in two separate unticked checkboxes on the results page — the report checkbox is required to receive the report; the marketing checkbox is independent, and refusing it does not affect the report. The anonymous session data (responses, scored result, hashed IP) is processed on the basis of our legitimate interest in providing the service and preventing abuse (Article 6(1)(f) GDPR); a balancing test is documented internally.

10.3 Retention

Session data (responses, result, itemsJson) is retained for 90 days from the date of the sitting and then automatically deleted by a scheduled cron. Hashed IP addresses are cleared 30 days after the sitting, ahead of the session purge. Email addresses persist for the same 90-day session lifetime; if you never verified the address, no report is sent and the address is deleted at the same time as the session. Marketing-opt-in preferences do not survive the session purge; a separate opt-in flow would be required to add you to any ongoing mailing list.

10.4 Processors and international transfers

We use the following third-party processors specifically for the proficiency test: Cloudflare (Turnstile challenge — jurisdiction: United States; safeguarded by adequacy decisions and standard contractual clauses); Resend (transactional email delivery — jurisdiction: United States; same safeguards). Session data is stored on our primary database at Neon (jurisdiction: European Union — Frankfurt region). PostHog receives only aggregate analytics events (see section 4) and no proficiency-test PII beyond a session identifier.

10.5 Your rights

You may exercise all GDPR rights over your test data — access, rectification, erasure, restriction, portability, objection — without holding a Vocabingo account. Every proficiency-test email includes a one-click "delete this test result" link. The same link is present on the results page you reach through your test URL. Deletion is immediate and irreversible: the session row, all associated responses, the email address (if provided), and the hashed IP are removed atomically. We do not require identity verification because the URL token functions as the credential.

10.6 No account required

Because the test is fully anonymous by default, we cannot correlate your test data with any Vocabingo account unless you were signed in at the time you took it. If you were signed in, your userId is stored alongside the session and your standard account-level data-subject request under /settings will include the linked test sessions in your data export. For sessions taken without signing in, the URL token remains the sole means of access and deletion.