Most of it never leaves your phone.

Who runs ThisBig

ThisBig is run by [Operator name: set THISBIG_OPERATOR_NAME], [Operator address: set THISBIG_OPERATOR_ADDRESS]. We decide what ThisBig collects and why, which makes us the data controller under Nigeria’s Data Protection Act 2023 (the NDPA) and, for people in the EU and the UK, the GDPR and the UK GDPR.

Write to [Privacy email: set THISBIG_PRIVACY_EMAIL] about anything on this page. Help with the app itself is on the support page.

What stays on your device

The app

• Your measurements: hand, height, feet, body measurements for clothes, garments that fit you, and spaces such as a car boot or a doorway.
• The people you buy shoes for: a name you choose, their foot size, and whether they’re still growing.
• Your last 20 comparisons, and your answers to “Did it fit?”.
• Screenshots and photos of tags. The text in them is recognised on the phone, by Apple’s Vision on iPhone and Google’s ML Kit on Android. Neither the picture nor its text is sent anywhere.
• The pictures you share. The drawing is made on the phone and goes only where you send it. If you’ve measured your hand, it can appear in the drawing at its real size.
• A “Buying me shoes?” link carries the sizes after the # in its address. Browsers never send that part to a server, so the page it opens reads them in your browser and we don’t see them.

Measurements and the people you buy for are kept in an encrypted store of their own, apart from history and settings. The key is built into the app, so it protects the file rather than the phone: anyone who can use your unlocked phone can open ThisBig. On iPhone the store is included in your phone’s backups. On Android, ThisBig is left out of backups.

The browser extension

• It reads product pages in your browser: the product’s name, its size details, the sizes on offer and the size chart. It doesn’t read prices, photos, reviews or anything you type into a page.
• It reads pages on its own on the shops it knows, such as Jumia, Konga, Jiji, Amazon, AliExpress, eBay and Etsy. Anywhere else, only when you click its button, right-click a highlighted size, or turn on Every other site too.
• In the browser’s own storage it keeps your sizes and the people you buy for, your settings, the last 30 pages you checked (their address, title and listing text), and your last 30 answers to “Did it fit?”.
• What it read for a tab is forgotten when you close the tab or leave the page.

This website

The size converter works in your browser and sends nothing. So does the comparator on the home page, until you paste a shop’s link into it: that link goes to our server to be read, as described under “Reading a link” below. The public pages set no cookies, run no analytics, and load their fonts from our own server. The only cookie on this site belongs to the staff console, for people signed in to it.

What reaches our server, and why

A random ID for your install

The first time the app opens, and the first time the extension needs our server, it registers a random ID made on the device, with which platform it is: Android, iOS or the extension. We send back a token that goes with every later request. That is how we limit requests, and how sync tells your devices apart. It isn’t your phone’s hardware or advertising ID, and on its own it doesn’t say who you are.

Reading a link

• The app sends a link you paste or share to our server as it is, including anything after the ?.
• This website sends a shop link you paste into the home page’s comparator, as it is. It reads only the shops ThisBig knows, and never sends the page to Claude.
• The extension sends a page’s link when its own reading isn’t sure of a size, with everything after the ? or # removed. It does this on its own on the shops it knows, and on any page where you click its button. When neither the page nor our server finds a size, it then sends the addresses of up to eight of the listing’s own photos, so our server can read a size printed on them. Turn both off in its Settings with Ask the server when unsure.

Our server fetches the page itself, so the shop sees a request from us, not from you. If our own reading isn’t confident, the page’s text, up to 20,000 characters, and its link go to Anthropic’s Claude to read the sizes. For an AliExpress link we may ask AliExpress’s catalogue instead, sending only the product number.

For photos, our server downloads each one from the shop’s own image server, reads its text on our server (no other company sees it), and deletes the photo. The text is kept for 30 days against the photo’s address, so the next person to look at the same listing doesn’t wait; it isn’t linked to you.

We record what was asked and what came back: the link, the sizes read, how sure the reading was, and your install’s ID when the app or the extension asked. A link pasted on this website has no ID with it. The answer is also cached against a fingerprint of the link for 30 days, so the next person to ask about the same listing gets it at once. The cached answer isn’t linked to anyone.

Correcting a unit

If you change the unit on a result we read from a link, the corrected sizes, the unit and the kind of thing go to our server, attached to our record of that link. The app does this whenever you correct one. The extension does it only once you turn on Send my corrections. Corrections tune the ranges that decide which unit a bare number is in.

Measuring on A4

When you photograph your hand or foot on a sheet of A4, 210 × 297 ⁠mm, the photo goes to our server, because that is where the measuring runs. It’s deleted as soon as the measuring finishes, whether it worked or not, and the result is kept for an hour for the app to collect. The measurements are saved on your phone, and reach our server again only if sync is on.

On Android the photo is sent as your camera app saved it, so it can carry details the camera added, such as when it was taken and, if your camera records it, where. We don’t read them, and they’re deleted with the photo.

Usage events, from the app

The app reports a fixed, short list of events so we can tell whether it works:

• a comparison was drawn, with the kind of thing, which reader read it and how long you waited; or it was refused, and why
• a drawing was shared
• the first comparison since the app was opened
• a size was saved, and how: told, from a chart or by tape. Never the size.
• a shoe or clothing listing got a fit answer: the kind, the outcome and how sure
• an answer to “Did it fit?”: right, too small or too big, with the listing’s brand
• the app hit an error and showed its recovery screen, with the first 64 characters of the error

Each event carries your install’s ID. None carries a size, a listing, a photo or anything about the people you buy for. There is no switch for them in the app yet. If you object to them, write to us. The extension sends none.

Signing in and sync

Sync is off until you sign in or link a device. When you sign in, Google or Apple confirms who you are and gives the app a signed token, which our server checks with them. From it we keep the provider’s ID for you, your email address if the provider has verified it (with Apple this can be a relay address that hides yours), and your name: your Google profile name, or the name Apple shares the first time only. We never see a password.

Once sync is on, these are kept on our server so every device you link sees the same:

• your hand, height and foot measurements, or the shoe size you told us instead
• your body measurements for clothes, and garments that fit you
• the people you buy for: the name you gave them, their foot length or size, and whether they’re still growing
• how your “Did it fit?” answers have adjusted a shoe size
• your spaces, with their names and sizes
• your recent comparisons in the app: what you checked and its size. The extension’s history stays in the browser.

Measurements, the names of spaces and your comparisons are encrypted in our database. We hold the key, so we could read them; none of our tools shows them to anyone. Some details aren’t encrypted yet: the names you give the people you buy for, whether they’re still growing, the brand and size system of a size you told us, and how “Did it fit?” has adjusted it.

Linking with a code

Instead of signing in, the extension can show an 8-character code for your phone to type in. It works once, for 10 minutes. If neither device had an account, we make one with no name or email, and sync starts as above.

The WhatsApp bot

If you message the bot, Meta’s WhatsApp service delivers your message to us with your phone number. A link is read as above. A screenshot is downloaded to be read and isn’t stored. Either way, what you sent is recorded like any other request, without an install ID. We use your number to reply, and to limit the bot to 30 messages an hour per number. Our log of the conversation keeps the number masked to its first six and last two digits, with the kind of message, our reply and how long it took.

Asking us to delete your account

The form at thisbig.app/account/delete asks for the email address on your account and, if you know it, which sign-in you used. We write to that address to confirm the request is yours before deleting anything.

Keeping it running

Your IP address reaches our server with every request, as it does with any website. We use it to limit how often one connection can ask, in counters that last a day at most. Errors are written to our server’s log so we can fix them. Our host’s own records: [Host access logs: confirm what the host records and for how long].

Who else handles it

We don’t sell anything about you, share it for advertising, or use any advertising or analytics service. These are the only other companies involved.

Anthropic

Its model, Claude, reads a listing’s text when our own reading isn’t confident. It gets the page’s text and link, or the caption of a screenshot sent to the bot. Never your install’s ID, your sizes or who you are. In the United States.

Meta

Delivers WhatsApp messages between you and the bot, if you use it.

Google

Sign in with Google, if you choose it. On Android, ML Kit recognises text on the phone and may send Google statistics about how it performs, never your pictures or their text. Google also distributes the app on Google Play and the extension on the Chrome Web Store.

Apple

Sign in with Apple, if you choose it, and the App Store.

Microsoft and Mozilla

Distribute the extension on Edge Add-ons and Firefox Add-ons.

AliExpress, and the shop you asked about

AliExpress gets a product number when you ask about one of its listings. Any shop sees our server fetch the page you asked about.

Our hosting provider

[Hosting provider and server location: confirm before publishing]

We would also disclose data if the law required it, and to whoever took ThisBig over, who would be bound by this policy.

How long we keep it

Where this says “no automatic expiry yet”, nothing deletes it on a schedule today. Deleting your account still removes everything marked “deleted with your account”.

Why we’re allowed to

The NDPA (section 25) and the GDPR (Article 6) each list the grounds on which personal data may be used. These are ours.

Data sent abroad

Our server is in [Server location: confirm before publishing]. Anthropic reads listing text in the United States, and Meta, Google and Apple run their services worldwide. So some of what you send leaves Nigeria, and leaves the EU or the UK if you’re there.

The NDPA allows this where the destination protects personal data adequately or the transfer has appropriate safeguards, and the GDPR sets similar conditions. Ours: [Transfer safeguards: confirm for each provider, e.g. standard contractual clauses].

Children

ThisBig is for adults and isn’t directed at children. Parents use it to buy shoes for their children, so you can save a child’s foot size and mark them as still growing. Recommended sizes then leave 10 ⁠mm at the toe to grow into.

That profile belongs to the parent’s app or browser. It holds the name you give (a nickname is fine), the foot length or a size, and the growing flag. We don’t ask for a birth date or a photo. It reaches our server only if you turn sync on, and goes when you delete it.

The NDPA treats anyone under 18 as a child; under the GDPR the age is between 13 and 16, depending on the country. If you think a child has given us personal data without a parent, write to us and we’ll delete it.

Your rights, and how to use them

Under the NDPA and the GDPR you can ask to see what we hold about you, have a copy to take elsewhere, correct it, delete it, restrict or object to how we use it, and withdraw consent you gave. ThisBig makes no automated decision about you with legal or similar effects: a size it recommends is a suggestion.

In the app, under My sizes

• Export everything we hold gives you a copy of what’s synced, to save or send. It needs sync on.
• Delete the copy on our servers deletes your synced measurements, people, spaces and comparisons for good, and turns sync off. Your account itself stays.
• Delete my account deletes the account itself, at once, as described under “Your whole account” below.
• Sign out on this device stops the phone syncing. It deletes nothing.
• Delete my measurements clears your measurements, people and spaces from the phone. With sync on, the next sync brings them back from our servers.

In the extension

Export my data saves a copy of what’s synced as a file. Unlink this browser stops it syncing and deletes nothing. Delete the copy on our servers deletes what’s synced and unlinks the browser. Delete my account deletes your whole account, as below. Removing the extension deletes everything it kept in the browser.

Your whole account

Delete my account, in the app or the extension, deletes it straight away. Without either, ask at thisbig.app/account/delete. Either way, once we know it’s you, we delete your account, everything synced to it, and what your devices sent us while linked to it: usage events, the links you asked us to read and the records of linking. Your devices keep working, without an account. We answer within 30 days.

Anything else

Write to [Privacy email: set THISBIG_PRIVACY_EMAIL]. We answer within a month. If you never signed in, what your app or extension sent us is tied only to its random ID, and we have no way to tell which records are yours.

Complaints

You can complain to the Nigeria Data Protection Commission. In the EU, to your country’s data protection authority; in the UK, to the Information Commissioner’s Office. We’d rather hear from you first.

Chrome Web Store: Limited Use

ThisBig’s use of information received from the browser extension adheres to the Chrome Web Store User Data Policy, including the Limited Use requirements. Information received from Sign in with Google adheres to the Google API Services User Data Policy, including the same requirements.

That means we use it only to show how big a product is and which size to buy, and to keep your devices in step. We transfer it only as this policy describes, to provide that. We don’t sell it, use it for advertising, or use it to decide anyone’s creditworthiness. Nobody reads it except with your permission, for security, to comply with the law, or, with nothing that identifies you, to improve how ThisBig reads listings.

Security

Everything between ThisBig and our server travels encrypted, over HTTPS. Measurements are encrypted in our database, the staff console needs an admin account, and A4 photos are deleted once measured. No system is perfectly secure. If a breach puts you at risk, we’ll tell you and the regulators as the law requires.