Privacy policy

Last updated: 2026-10-18

Lexido is a language-learning flashcard app for iOS. This page says what the app sends off your device, what we keep, who can see it, and how to delete it.

You can use Lexido without an account

Studying, the starter decks, lessons and review scheduling all work without signing in. An account is optional. You only need one for Friends and for keeping Lexido Pro when you switch to another iPhone or iPad.

The device identifier

The first time you open Lexido, the app generates a random identifier and stores it in your device’s keychain. It is not your name, your email or your Apple ID, and it means nothing outside Lexido.

That identifier is sent with requests the app makes to our backend. We use it to:

Know whether your Lexido Pro subscription is active.
Count how much AI generation you have used, so we can apply the free allowance and your plan’s monthly limit.

We do not use it for advertising, we do not use it to track you across other apps or websites, and we do not sell or share it.

If you choose to sign in, Lexido uses Sign in with Apple. We do not ask Apple for your name or your email address, so we never receive them. What we receive is the user identifier Apple assigns to you for Lexido. It is the same on all your devices, which is how your account and your Pro subscription follow you from one device to another.

When you sign in, we create an account record that holds:

The Apple user identifier for Lexido.
A friend code, a short random code that friends use to add you.
A sign-in token for each device you sign in on. We store only a scrambled form of it, never the token itself.
Which of your devices are linked to the account, so a subscription bought on one of them counts on all of them.

Signing out removes the sign-in token from that device and from our backend.

Friends

Friends is optional and only works when you are signed in.

Your name. You can choose a display name in Settings, Account, Name. It can be anything you like, up to 24 characters. If you leave it empty, friends see your friend code instead.
What friends see. Your display name (or friend code), your current streak, your best streak, the day you last studied, and how many words you have mastered. Nothing else. Friends do not see your decks, your cards, your reviews, your stories or your subscription.
Who sees it. Only people who have added your friend code, and people you have added. Someone can only add you if they have your code, and the only way to get it is for you to share it. Nobody can search for you, and there is no public profile.
How it gets there. Your streak and mastered-word count are worked out on your device. The app then sends us those few numbers so your friends can see them. Your review history itself stays on your device.
Removing a friend takes them off your list right away.

What stays on your device

Your review history and progress. Card ratings, scheduling, and daily counts are stored only in the app’s database on your device. They are not uploaded.
Your cards and decks.
App settings such as your languages, sound options and reminder preferences. Study reminders are scheduled on your device. We do not send push notifications.

If you uninstall the app, all of this is gone with it.

What leaves your device

Lexido contacts our backend (hosted on Cloudflare) when you use a feature that needs it.

Starter decks and lessons. The app downloads cards, pictures and audio from our shared library.
Songs. When you search for a song, the search text goes to Apple’s music search through our backend. The song’s lyrics are fetched from lrclib.net, a community lyrics database, and used to find the words you don’t know yet. The app shows only the short lines that contain your new words. Neither Apple’s search nor lrclib receives any identifier of yours.
Creating cards and stories. The language, the words or theme you typed, and the resulting word list go to our backend, which calls the AI services listed below.
Word lookups. A sentence or lyric line you tap is sent to our backend to be split into words and looked up.
Friends, as described above, when you are signed in.

For these requests, our backend may keep:

Stories you generate. We store each story with its pictures and audio, tagged with your identifier, so it can be shown back to you. Only you can see the stories you generate. They are never shown to other learners.
Generated content (cards, pictures, audio) in a shared library, so the same word loads instantly for the next person who studies it. This library is keyed on the language and the word, and is not linked to you.
Operational logs: which feature was used, how long it took, how many cards were made, and the text you typed for AI requests. We use them to find bugs and outages. Logs carry a one-way scrambled tag in place of your identifier, and a one-way scrambled tag in place of your IP address, which we use to stop one device from overloading the AI features. We cannot turn either tag back into the original, and we do not store your IP address.

Use of AI

Lexido uses AI to make flashcard and story content:

Example sentences, meanings, word lists and stories come from language models (OpenAI, Google, Qwen, DeepSeek and Mistral models, routed through OpenRouter).
Card and story pictures come from Cloudflare Workers AI and, sometimes, Google Gemini image generation.
Audio comes from Microsoft Azure Speech.

These services receive only the language and the words, theme or lyric lines needed for the request. None of them receive your identifier, your Apple user identifier, your display name or your friend code.

Usage analytics and diagnostics

Lexido collects a small amount of first-party usage and diagnostic data, sent to our own backend. We do not use a third-party analytics SDK, and none of this is used to track you across other apps or websites.

Usage analytics. Which screens you reach and which features you start and finish, so we can see where the app confuses people. These events carry a separate random identifier, generated on first launch and stored on the device. It is not the identifier used for your subscription or your account, and the two are never joined, so this data is not linked to you.
Diagnostics. When something goes wrong, we send the error, the screen it happened on, and the recent in-app steps that led to it, so we can fix it.

Subscriptions

If you subscribe to Lexido Pro, the App Store handles the purchase. Apple sends us:

The transaction identifier for your subscription.
The product you bought (monthly or yearly) and its current status.

We store this against your device identifier, and against your account if you are signed in, so your Pro features work on your devices. We never see your Apple ID email or your payment details. Cancellation and refunds go through Apple, in Settings, your name, Subscriptions.

We also keep a monthly count of how much AI generation you have used, to apply your plan’s monthly limit, and a count of the free cards used before subscribing.

What we don’t collect

No email address, no real name unless you type one as your display name, no phone number, no password.
No advertising identifier (IDFA), and no tracking across other apps or websites.
No third-party analytics SDKs.
No location, contacts, photos, microphone or camera access.
No upload of your review history.

Deleting your data

Delete your account in the app in Settings, Account, Delete account (also at the bottom of Settings). This permanently deletes, from our backend:

Your account record and Apple user identifier.
Your display name, friend code, streak and mastered-word count.
Your friend list, in both directions, so you disappear from your friends’ lists.
Every sign-in token for the account.
Any study progress stored for your identifier.
The stories generated for you, the devices linked to your account, and your free-card allowance.

The record of your subscription purchase is kept, because the subscription keeps running at Apple until you cancel it and the purchase record is needed to honor it.

The app then wipes its local database and generates a fresh device identifier. Your subscription itself is managed by Apple and is not cancelled by deleting your account; cancel it in your iPhone’s Settings.

Uninstalling the app removes everything stored on the device, including the separate analytics identifier.

Usage and diagnostic events already sent are not linked to you and cannot be looked up per person, so they are removed on our retention schedule rather than on request. If you want them removed sooner, email us.

Your rights

If you want to know what we hold, or want it erased, email support@getlexido.com and we will do it. Depending on where you live, you may have more rights over your personal data, including access, correction, erasure and portability. The same address is how to use them, and we will not charge you or make it difficult.

Children

Lexido is not directed at children under 13, and we do not knowingly collect personal data from them. There is no advertising and no messaging between users. If you believe a child has given us personal data, email support@getlexido.com and we will delete it.

Third parties

Apple handles Sign in with Apple, subscriptions, payment and song search.
Cloudflare runs our backend, stores generated content, and draws some pictures. Cloudflare’s privacy policy.
Turso hosts our database. Turso’s privacy policy.
OpenRouter routes language model requests to OpenAI, Google, Qwen, DeepSeek and Mistral models. OpenRouter’s privacy policy.
Microsoft Azure Speech makes the audio for cards.
lrclib.net supplies song lyrics.

We send these services only what is needed for your request. None of the AI or lyrics services receive any identifier we hold for you.

Changes

If we add features that change what leaves your device, such as syncing your review history between devices, we will update this page and tell you in the app before the feature turns on.

Contact

Questions about this policy? Email support@getlexido.com.

Lexido is operated by Heltra LLC.