How SizeLight handles your data

Who we are

SizeLight is made by Boumora Labs (“we”, “us”). We decide how the personal data described here is used, which makes us its “controller” under data protection law such as the GDPR and UK GDPR.

For anything about your privacy, email hello@sizelight.com.

The website

Your pattern PDFs

When you open a PDF on sizelight.com, your browser reads it on your device. The file, its name, its text and the numbers in it are never sent to us or to anyone else. The sample pattern is our own file, downloaded from our website like any other page.

What’s saved in your browser

The website keeps a few things in your browser’s local storage:

• the last size you picked (for example “M”), to preselect it next time;
• for the suggestion to keep your patterns in the app: whether you’ve opened the waitlist form, when the suggestion was last shown, how many times in a row you let it pass, and when you last chose “Not now”. That keeps it rare: at most once a week, not for 30 days after “Not now” or after you’ve let it pass twice, and never again once you’ve opened the form;
• the sizes you confirmed or entered for a pattern;
• your yes or no answers to “Is this a size number?” for a pattern.

The last two are filed under a fingerprint of the PDF (a SHA-256 hash of the file) that your browser works out itself, so they come back when you open the same file again. None of this is sent to us. To remove it, clear this site’s data in your browser’s settings. SizeLight sets no cookies.

Usage counts (analytics)

To learn whether SizeLight is useful and what to fix, we use PostHog, on its EU Cloud. It runs in cookieless mode: it sets no cookies, stores nothing in your browser and gives you no ID that follows you around. Requests go through our own address (sizelight.com/ingest) to PostHog’s EU servers. Session recording, click tracking and heatmaps are all switched off.

What’s sent:

• Page views. Which of our pages you visited, the site that linked you here, any campaign tags in the link (such as “utm_source”), your browser, operating system and type of device, screen and window size, language and time zone. When you leave a page: how long you stayed and how far you scrolled.
• These events, and no others:
  • The pattern tool loaded.
  • The pattern tool can’t run in this browser, and which browser feature is missing (for example “resize-observer”).
  • The sample pattern was opened.
  • A PDF was opened: its number of pages, a rough file-size range (such as “500–2000 KB”), and whether it was the sample.
  • A PDF couldn’t be read, and why: not a PDF, too large, password-protected, damaged, a scan, unreadable text, or another problem.
  • Sizes were found: how many sizes, whether SizeLight was sure of the size list, how many numbers it highlighted and how many it wasn’t sure about.
  • You confirmed or corrected the size list: how many sizes, and whether you changed the number of sizes.
  • You picked a size: where it sits in the list (for example the 3rd of 5) and how many sizes there are. Not the size’s name.
  • You answered “Is this a size number?”: yes or no.
  • You tapped “Wrong highlight?”: whether it was a number SizeLight was sure or unsure about.
  • You opened the waitlist form, and where on the page its button was.
  • You sent the waitlist form, and where on the page its button was. Never your answers.
  • After you picked a size in one of your own PDFs, the suggestion to keep your patterns in the app was shown.
  • You chose “Join the app waitlist” on that suggestion.
  • You chose “Not now” on that suggestion.
  Each of these events also carries the same page and device details as a page view (the page address, the site that linked you here, your browser, operating system, type of device, screen size, language and time zone).

Events never include a pattern’s text, its file name, its size names or the numbers in its instructions, only counts like the ones above. Any other event is dropped in your browser before it’s sent.

Like every request on the internet, these requests carry your IP address and your browser’s user agent. PostHog uses them, together with a secret that changes every day, to count unique visitors without cookies, so a visitor can’t be recognised from one day to the next. PostHog stores your IP address with each event and uses it to work out an approximate location (country, city and an approximate position). We don’t use your IP address to identify you, and we don’t combine it with anything else we hold.

Why: our legitimate interest in understanding, without identifying anyone, whether SizeLight works and what to improve.

Website hosting

The website is hosted by Vercel. Like any web host, Vercel’s servers receive your IP address, the page you asked for and your browser’s user agent with each request, and keep short-lived logs to run and protect the service.

Why: our legitimate interest in running a secure, working website.

The app waitlist

If you join the waitlist for the app, the form is provided by Tally. It asks for:

• your email address;
• what you make (knitting, crochet or both);
• which phone you have (iPhone or Android);
• your favourite pattern designers (optional).

Our page also passes two details to the form: where on the page the button you used was, and how many sizes SizeLight found in the pattern you had open (a number only, 0 if none).

We use this to tell you when the app is ready and to decide what to build first, for example iPhone or Android. Your answers stay in Tally: they’re never sent to our analytics, which only counts that the form was opened or sent.

Tally’s form script is loaded from tally.so only when a waitlist button is about to come into view, or when you point at or select one, and never after you’ve opened a pattern on the page. The waitlist buttons next to an open pattern open Tally’s form in a new tab instead. Either way, your browser connects to Tally, which receives your IP address and browser details and may set its own cookies under its privacy policy.

Why: your consent, which you give by sending the form. You can withdraw it at any time by emailing hello@sizelight.com, and we’ll remove your answers.

Emails you send us

When you email hello@sizelight.com, Cloudflare forwards your message to our mailbox, which is hosted by Google (Gmail). We use your email address and what you write only to reply and to help, for example to fix a pattern SizeLight read wrongly.

Why: our legitimate interest in answering you, or taking the steps you ask us to take.

The SizeLight app

The app isn’t in the App Store or Google Play yet. This section describes it as it’s built today, and we’ll update it before release if anything changes.

Your patterns stay on your phone

The PDFs you add are copied into the app’s own storage on your phone and read there. They’re never uploaded to us or anyone else.

What the app saves on your phone

For each pattern, in a database on your phone:

• its name, when you added it and when you last opened it, and its number of pages;
• a fingerprint of the file (a SHA-256 hash), so the same PDF isn’t added twice;
• its size list, the size you chose, and your answers to “Is this a size number?”;
• your row counter, line marker, zoom and place in the pattern.

It also remembers the last size you chose and whether to keep the screen awake. None of this is sent anywhere.

What the app sends

Nothing. The app has no account, no analytics, no advertising and no tracking, and doesn’t send your patterns or how you use the app to us or anyone else. The “Contact us” and “Privacy policy” links in its settings open your email app or your browser.

If you’ve allowed it in your phone’s settings, Apple or Google may share crash reports and basic, aggregated app statistics with us through the App Store and Google Play developer tools. These never include your patterns or their names.

Backups and app stores

Like other apps’ files, SizeLight’s storage can be included in your phone’s own backups (iCloud Backup on iPhone, Google backup on Android). Those backups, and app downloads from the App Store and Google Play, are handled by Apple and Google under their own privacy policies.

Deleting your data

To delete a pattern, press and hold it in your library, then choose Delete. This removes its PDF and everything saved about it. Uninstalling SizeLight removes all of it from your phone; copies in your phone’s own backups follow your backup settings.

What we don’t collect

• Your patterns: not the files, their names, their text, or the numbers and sizes in them.
• No accounts or passwords. We only know your email address if you join the waitlist or email us.
• No cookies from SizeLight, and no advertising or cross-site tracking.
• No session recordings, click tracking or heatmaps.
• No access to your camera, microphone or your device’s location: the website tells your browser to block them.
• We don’t sell your personal information or share it for targeted advertising.

Services we use

We use these companies to run SizeLight. They receive the data described above to provide their service, and may also use it to keep their service secure. Each has its own privacy policy.

• VercelHosts the website. Its servers handle every request to sizelight.com and pass analytics requests on to PostHog.Vercel’s privacy policy
• PostHog (EU Cloud)Cookieless website analytics that don’t identify you, stored in PostHog’s EU region.PostHog’s privacy policy
• TallyThe app waitlist form, and the answers you give in it.Tally’s privacy policy
• CloudflareRuns the domain name (DNS) for sizelight.com and forwards emails sent to hello@sizelight.com. Website traffic doesn’t go through Cloudflare.Cloudflare’s privacy policy
• Google (Gmail)The mailbox (Gmail) that emails to hello@sizelight.com are forwarded to.Google’s privacy policy

Vercel, Cloudflare and Google are based in the United States, and PostHog’s parent company is too (our analytics are stored in its EU region). Tally is based in Belgium, in the EU. Where data is transferred outside the UK or the European Economic Area, it’s protected by the safeguards data protection law requires, such as the EU–US Data Privacy Framework or Standard Contractual Clauses.

How long we keep it

• On your device (browser storage and the app’s data): until you clear it, delete the pattern or uninstall the app. We can’t see it or delete it for you.
• Waitlist answers: until the app is released and we’ve told you about it, and then no longer than 6 months, or sooner if you ask us to remove them.
• Emails: for as long as we need them to help you. Ask and we’ll delete them.
• Analytics: kept in PostHog for up to 12 months, then deleted, and not linked to your name or email address.
• Hosting logs: kept for a short time by Vercel, under its own retention rules.

Your rights

You can ask us to:

• tell you what personal data we hold about you, and give you a copy;
• correct it;
• delete it;
• stop or limit how we use it, or object to it;
• give it to you in a format you can take elsewhere;
• withdraw your consent, for example by leaving the waitlist.

These are your rights under the GDPR and UK GDPR, and people in California and many other places have similar rights under their own laws. We’ll honour these requests wherever you live.

Email hello@sizelight.com from the address your request is about. We’ll reply within one month (or tell you within that month if we need longer for a complex request, as the law allows), and you won’t be treated differently for asking. Because our analytics are cookieless and have no ID for you, we can’t find the events that came from you, so we can’t show or delete them one by one.

If you’re unhappy with how we handle your data, you can also complain to your data protection authority, such as the ICO in the UK or the authority in your EU country.

Children

SizeLight isn’t aimed at children, and we don’t knowingly collect personal data from anyone under 16. If you think a child has joined the waitlist, email hello@sizelight.com and we’ll delete it.

Changes to this policy

If this policy changes, we’ll update this page and the “Last updated” date at the top. If a change affects what we collect, we’ll say so clearly on the website.

Contact

Boumora Labs, the maker of SizeLight
Email: hello@sizelight.com