Privacy policy

1. Information we collect

Account information: When you register, we collect your email address and password (stored as a salted hash). You may optionally provide a display name.

Usage data: We collect information about how you use Spark — pages visited, features used, reading sessions, vocabulary interactions, and streak activity. This helps us improve the product.

Imported content: Articles, books, and video transcripts you import are stored so we can render them in the reader. This content is private to your account.

Payment information: Payments are processed by Stripe. We never store your full card number. Stripe may collect and process billing information in accordance with their privacy policy.

Device & technical data: Browser type, operating system, IP address, and error logs may be collected automatically for security and debugging purposes.

2. How we use your information

• To provide, operate, and improve the Spark service
• To personalise your experience (e.g., vocabulary state, CEFR progress, daily targets)
• To process payments and manage subscriptions
• To send account emails (password reset, email verification)
• To send product updates and newsletters — you can opt out at any time
• To detect and prevent fraud or abuse
• To comply with legal obligations

3. Sharing your information

We do not sell your personal data. We share data only with the limited set of third-party services necessary to operate Spark:

• Stripe — payment processing
• Google Cloud — Spark AI features, through Vertex AI (Gemini), Cloud Translation and Cloud Speech-to-Text (imported or selected text, vocabulary context, and audio you record for speech practice are sent to generate narration, translations, explanations and transcripts; no account info is shared)
• Firebase (Google) — sign-in and hosting
• PostHog — product analytics (anonymised usage events)
• Help Scout — customer support (only if you contact us)
• Beehiiv — email newsletter (only if you subscribe)
• PromoteKit — affiliate referral tracking (only if you arrive through an affiliate link)
• AI assistants you connect (Claude, ChatGPT) — only if you connect one yourself; see section 4

We may disclose information if required by law, court order, or to protect the rights, safety, or property of Spark or its users.

4. AI assistants you connect (Claude, ChatGPT)

On Core and Plus you can connect Spark to an AI assistant such as Claude (by Anthropic) or ChatGPT (by OpenAI), so it can talk to you at your level. Nothing is shared until you add the connection in that assistant and choose Allow on Spark's sign-in page.

What the assistant can read: your learning and native language, your rough level, how many words you know, the words you are currently learning, and — when you ask it to — your notes and highlights. It can also send Spark a reply it has drafted, and Spark tells it which words in that reply are new to you.

What Spark receives and keeps:

• Drafts the assistant checks are used only to count new words. Spark does not store them.
• A conversation is stored only when you ask the assistant to save it to Spark (available in Claude). It then appears as a chat in your account, and the words you typed that Spark had as Unknown are marked as Known. It stays until you delete it or your account.
• A record of each connection: which app, when it was connected and last used. Spark stores sign-in tokens only in scrambled (hashed) form.
• Our logs record counts and timings (for example, how many words were new), never the text of a draft, a note or a chat.

What we never do: use your saved conversations or drafts to train any AI model, or to tune Spark's own chat. We do not read the rest of your assistant history, its memory or files you uploaded to it — only what the assistant sends us through the connection.

Your controls: disconnect an app at any time in Spark under Profile → Connections; its access ends immediately. You can delete any saved chat in Spark.

What the assistant itself does with your conversation is governed by its provider's policy: Anthropic for Claude, OpenAI for ChatGPT. More about the connection: Spark in Claude and ChatGPT.

5. Data retention

We retain your account data for as long as your account is active. If you delete your account, we will delete your personal data within 30 days, except where we are required to retain it for legal or compliance reasons.

6. Your rights

Depending on your location, you may have the right to:

• Access the personal data we hold about you
• Correct inaccurate data
• Delete your account and associated data
• Export your vocabulary and reading data
• Object to certain processing activities

To exercise any of these rights, email us at matt@learnwithspark.io.

7. Cookies

Spark uses minimal cookies and local storage to keep you logged in and remember your preferences. Our website and app also set a first-party PostHog analytics cookie so we can see which pages people visit and how they found us. We do not use advertising cookies or third-party tracking cookies.

8. Security

We use industry-standard security practices including HTTPS encryption, hashed passwords, and access controls. No system is perfectly secure — if you believe your account has been compromised, contact us immediately.

9. Children

Spark is not directed to children under 13. We do not knowingly collect personal information from children. If you believe a child has provided us personal data, please contact us and we will delete it.

10. Changes to this policy

We may update this Privacy Policy from time to time. We will notify you of material changes by email or by posting a notice in the app. Continued use of Spark after changes take effect constitutes your acceptance of the updated policy.

11. Contact

Questions about this policy? Email us at matt@learnwithspark.io or visit our Contact page.