Privacy Policy

This Privacy Policy explains what data Custom Font (“we”, “us”) collects when you use customfont.app (the “Service”), why we collect it, and what choices you have. It applies alongside our Terms of Service.

We try to collect as little as possible. Most of your handwriting work stays on your device.

1. Short version

• Your handwriting photos and drawn glyphs are processed in your browser. We do not store the source images on our servers.
• If you ask the AI to fill in missing characters, your sample glyph images are sent to Anthropic for that single request and are not retained by us.
• If you sign in, we store your email and a user ID via Supabase.
• If you pay, Stripe processes the payment. We never see your card number.
• We log IP addresses briefly in memory to rate-limit abuse and use Vercel analytics for aggregate traffic stats.

2. What we collect and why

a) Handwriting samples (photos, drawings, glyph data)

When you upload a photo or draw letters in the browser, the image and glyph data are processed locally and stored in your browser's sessionStorage / localStorage so you can come back to your work-in-progress. They are not uploaded to our servers in the normal flow.

The exception is the optional “generate missing glyphs with AI” feature: if you choose to use it, up to eight of your sample glyph images are sent to Anthropic's Claude API in a single request so the model can produce the missing characters. We do not retain those images after the request completes. Anthropic's handling of API inputs is governed by Anthropic's privacy policy.

b) Account information

If you sign in (currently via email + magic-link or OAuth provider), we store your email address, a user ID, and basic profile metadata via Supabase, our authentication and database provider. We use this to identify you across sessions, remember your purchases and saved fonts, and contact you about service-related matters.

c) Payment information

Payments are processed by Stripe, Inc. Stripe collects your card or bank details directly — we never see or store them. We do store an internal Stripe customer ID against your account so we can fulfil credits, manage subscriptions, and provide receipts. Stripe's handling is governed by Stripe's privacy policy.

d) IP address and request metadata

Our API routes briefly read your IP address to apply per-IP rate limits and detect abuse. The IP is held in memory on the serverless instance for a short rolling window and is not written to a database by us. Standard request logs may be retained by our hosting provider, Vercel, for operational purposes.

e) Analytics and performance

We use Vercel Analytics and Vercel Speed Insights to understand aggregate traffic and page performance. These tools are designed to be privacy-friendly and do not use third-party cookies. Vercel's handling is governed by Vercel's privacy policy.

f) Cookies and local storage

We use essential cookies and browser storage only — for authentication (Supabase session), payment flow (Stripe), and remembering your in-progress font. We do not use third-party advertising or tracking cookies.

3. How we use your data

We use the data described above to:

• Operate the Service — process glyphs, assemble fonts, and serve downloads.
• Authenticate you and remember your saved fonts and purchases.
• Process payments and provide receipts.
• Prevent abuse (rate limiting, fraud, IP-based throttling).
• Diagnose bugs and improve performance.
• Respond to support requests and legal notices.

We do not sell your personal data. We do not use your handwriting or generated fonts to train any model.

4. Who we share data with

We share data only with the third-party processors listed above, each strictly to provide the function we use them for:

• Vercel — hosting and analytics.
• Supabase — authentication and database.
• Stripe — payments and subscription management.
• Anthropic — AI glyph generation (only if you use that feature).

We may also disclose data if required by law, to enforce our Terms, or to protect the rights, property, or safety of Custom Font, our users, or the public.

5. International transfers

Our processors operate globally and your data may be processed in countries other than your own, including the United States. We rely on the standard contractual terms and safeguards published by each processor for these transfers.

6. Retention

We retain account data for as long as your account is active and for a reasonable period afterward to handle support, billing, and legal requirements. Handwriting samples remain on your device until you clear them (or until your browser clears storage). Payment records are retained as required by tax and accounting law.

7. Your rights

Depending on where you live, you may have rights to access, correct, delete, port, restrict, or object to our processing of your personal data, and to withdraw consent at any time. To exercise these rights, email hello@customfont.app. We will respond within the timeframe required by your local law.

If you are in the UK or EU, you can also lodge a complaint with your local data protection authority. If you are in California, you have additional rights under the CCPA/CPRA, including the right to know and the right to delete; we do not “sell” or “share” personal information as those terms are defined under California law.

8. Children

The Service is not directed to children under 13 (or the equivalent minimum age in your country) and we do not knowingly collect personal information from them. If you believe a child has provided us with personal information, contact us and we will delete it.

9. Security

We rely on HTTPS in transit, our processors' security controls, and least-privilege access on the server side. No system is perfectly secure, and we cannot guarantee absolute security of any data.

10. Changes to this Policy

We may update this Privacy Policy from time to time. When we make material changes we will update the “Last updated” date and, where appropriate, notify you in the Service.