Privacy Policy — Stitchsums

The short version

Stitchsums collects almost nothing. The calculators run entirely in your browser — your inputs never leave your device. We use a privacy-first analytics service (Vercel Web Analytics) that records aggregated page views without cookies, without personal data, and without cross-site tracking. There is no signup, no behavioural advertising, and no third-party ad tech on this site.

Two optional features — Ask and the AI pattern PDF — send what you type to an AI provider so it can answer. They are described under AI features below.

When affiliate links are added (see our Affiliate Disclosure ), clicks route to the retailer — at that point you become their visitor under their privacy terms, which we link to wherever those links appear.

What we collect

We use Vercel Web Analytics — cookie-free, anonymous analytics from the company that hosts this site — on stitchsums.com and on the chart editor. It records:

The page you visited, and when
The referrer (the previous URL, if any)
Your browser, operating system and device type (e.g., "Safari on iOS, tablet")
Your approximate location (country, region and city), not tied to you or to your IP address
In the chart editor only, three actions: starting a chart, downloading a PDF and downloading a picture, along with the craft chosen

Vercel Web Analytics does not use cookies and does not track you across sites. Visitors are counted with an anonymous code made from the request that is thrown away after 24 hours, so there is no lasting identifier. The data is aggregated — we cannot identify individual visitors from it. Your pictures and charts never leave your device.

What stays in your browser

The following data lives in your browser only — it is never sent to Stitchsums:

Calculator inputs and results. Every calculator on this site is a pure function — your numbers go in, the answer comes out, no network request is made (unless you choose to use one of the AI features below). You can verify this by opening your browser's Network tab while you use a calculator: it stays silent.
Your display preferences. We keep a few small items in your browser's localStorage so the site remembers your choices: light or dark mode, your accent colour, and inches or centimetres. Clear them any time via your browser settings.
Charts you make in the chart editor. Your current chart and your most recent ones are saved in your browser's own storage on your device, so they are there when you come back. Pictures you turn into patterns are processed on your device and are not uploaded. Clearing your browser's site data removes them.

No other data is stored in your browser by Stitchsums. No cookies. No fingerprints. No session identifiers.

Third parties on this site

Stitchsums loads resources from these third parties. Each one is named so you can review their own privacy practices:

Vercel — hosting and cookieless Web Analytics. Their analytics privacy page.
Anthropic, through Vercel's AI Gateway — only when you use Ask or the AI pattern PDF. The text you type is processed by Anthropic's Claude models. Anthropic's privacy policy; Vercel's privacy policy.
Cloudflare Turnstile — a bot check on the two AI pages. Cloudflare's privacy policy.
Resend — delivers the AI pattern PDF to the email address you give. Resend's privacy policy.
Affiliate retailers (Amazon, LoveCrafts, WeCrochet, Awin merchants) — only when you click an affiliate link. See our Affiliate Disclosure.

We do not use Google Analytics, Facebook Pixel, advertising retargeting, session replay tools (Hotjar, FullStory), or any behavioural tracking service.

AI features: what gets sent

Two features on Stitchsums use an AI model. Everything else on the site, including every calculator and the chart editor, works without one.

Ask (the question box). When you ask a question, the text you type and the earlier messages in that conversation are sent from our server to an AI model (Anthropic's Claude, reached through Vercel's AI Gateway) so it can work out which calculation you need. The numbers in the answer come from our own tested calculators, not from the AI. We do not store your questions or the answers, and there is no account or history: when you close the page, the conversation is gone from our side.
AI pattern PDF. When you request a pattern PDF, the description you type is sent to the same AI model to turn it into calculator inputs. The email address you enter is used once, to send you the PDF through our email provider (Resend). We do not add it to a mailing list.

Please don't put personal details in your questions. They aren't needed, and anything you type is passed to the AI provider. Vercel's AI Gateway lists the models we use as ones whose providers do not train on what is sent. The providers named above handle what they receive under their own privacy policies, which may include keeping requests for a limited time.

Checking you're a person. Both features use Cloudflare Turnstile to keep bots out. Turnstile looks at signals from your browser and your IP address to decide whether you're human. To stop abuse we also count requests per IP address for a short time; this count is kept only in memory and is not saved.

Planned: Pro accounts

A paid tier is planned: an account (email sign-in), saved patterns and projects, and payment handled by Stripe, so we would never see your card details. It does not exist yet. This policy will be updated before it launches.

Cookies

Stitchsums sets no cookies. None. The only browser storage we use is described above — your display preferences and, in the chart editor, your charts — which is not a cookie and is not sent in HTTP headers. On the two AI pages, Cloudflare's Turnstile bot check runs in your browser under Cloudflare's own policy.

Children's privacy

Stitchsums is not directed at children under 13 (or under 16 in EU jurisdictions where the GDPR age-of-consent is higher). We do not knowingly collect data from children. Since we collect almost no data from anyone, this is mostly moot — but if you believe a child has been identified through this site, contact us and we will investigate.

Your rights

Under GDPR (EU), UK GDPR, CCPA (California), and similar laws elsewhere, you have the right to access, correct, or delete personal data we hold about you. Because Stitchsums does not currently identify individuals, there is no personal data attached to you on our side — the analytics aggregates cannot be tied to a specific visitor. The one exception is the AI pattern PDF: the email address you enter passes through our email provider to deliver it. Ask us and we will have any record of it removed.

If a future feature (such as a Pro account) creates personal data about you, you will be able to access, export, or delete it from your account dashboard. Until then, requests can be sent to hello@stitchsums.com and we will respond within 30 days.

International transfers

Our host and analytics provider, Vercel, is a US company, so the anonymous analytics described above may be processed in the United States. The providers behind the AI features (Anthropic, Vercel, Cloudflare and Resend) are also US companies, so what you send through those features may be processed there. Our static site is served from a global CDN — your request is routed to the nearest edge location for performance, but no personal data is processed at the edge beyond standard HTTP request handling. If you reach an affiliate retailer through one of our links, that retailer's data residency is described in their own privacy policy.

Changes to this policy

When we change this policy materially — for example, when the Pro account ships and starts collecting data — we will update the "Last updated" date above and surface a brief change summary on this page for at least 30 days. We will not retroactively apply weaker terms to data already collected under stronger ones.

Contact

Privacy questions, data requests, or concerns about the practices above can be sent to hello@stitchsums.com.