Privacy policy
Last updated 12 September 2026. Applies to the LangBuddy
mobile app (com.mike101.langbuddy) for iOS and Android, and to
this website.
The short version. LangBuddy has no account and no server. Your vocabulary, your settings and your backups live on your phone. We collect nothing, we store nothing about you, and there is no analytics, advertising or tracking in the app. The only data that ever leaves your device is text you have asked to have translated, sent directly to the AI provider you chose, using your own API key.
Who is responsible
LangBuddy is made by zhware, an individual developer. Questions about this policy: langbuddy.support@zhware.org.
What LangBuddy stores, and where
Everything below is stored only on your device, in the app’s own private storage. None of it is transmitted to us, because there is nowhere to transmit it to.
- Your vocabulary — the words, phrases and sentences you capture, their translations, pronunciations, explanations and example sentences, the source you noted, and any tags and notes you add.
- Your revision history — how often each word has been quizzed, how often you got it right, and when you last looked at it.
- Your settings — the languages you study, the interface language, theme, reminder time and similar preferences.
- Backups — the app writes periodic JSON exports of your vocabulary into its own documents folder on the device. They are not uploaded anywhere.
- Your API key, if you add one — held in the iOS Keychain or the Android encrypted preference store, and sent only to the provider it belongs to.
LangBuddy does not collect your name, email address, phone number, contacts, photos, location, advertising identifier or device identifier. It contains no analytics, crash-reporting or advertising SDK.
What leaves your device, and when
On-device translation (the default)
LangBuddy translates on the device first, using the translation engine built into your operating system. That engine may download language models from the platform vendor (Apple or Google) the first time a language pair is used; after that it works offline. This is handled by the operating system, not by LangBuddy, and the text you translate is processed on the device.
AI providers (only if you set one up)
You may optionally configure an AI provider — DeepSeek, OpenAI, Google Gemini, Anthropic or OpenRouter — by entering an API key you obtained yourself. When one is configured, LangBuddy sends that provider:
- the word, phrase or sentence you captured;
- the source you noted for it, if any, which is sent as context;
- the description you type when you ask for a made-up quiz;
- the languages you have configured.
The request goes directly from your phone to that provider. It does not pass through any server of ours. What the provider does with it is governed by their privacy policy and the terms of the account your key belongs to — please read them before entering a key. You can remove the key at any time in Settings, and the app falls back to on-device translation.
Nothing else
There is no other network activity. LangBuddy does not check in, does not report usage, and works entirely offline once your language models are downloaded and if no AI provider is configured.
Notifications
The optional daily reminder is a local notification scheduled on the device itself. There is no push service and no server involved, and the reminder is only scheduled when something will actually be due when it fires.
Support requests and bug reports
The report form at /report/ posts to Web3Forms, a third-party form relay, which forwards it to our support mailbox. It receives what you typed, the email address you gave if you gave one, and the app details shown to you on that page. The form takes text only; there is no file upload. Web3Forms processes it as a data processor on our behalf; see their own privacy terms. If you would rather not use it, email us instead — the address is on the same page.
If you email support, we receive whatever you put in that email — typically your email address, your description of the problem, and any diagnostics you chose to paste in. The diagnostics the app can copy for you contain the app version, the platform, your configured language codes, the name of the AI provider and model you selected, and how many entries you have. They never contain your API key, and they never contain your vocabulary.
Support mail is used only to answer you, is never used for marketing, is never sold or shared, and is deleted once the matter is closed.
This website
This site is static and is hosted on GitHub Pages. It sets no cookies, runs no analytics and embeds no third-party scripts or fonts. The one script on it is a few lines of our own on the report page, which copies the app details out of the link the app opened it with so you can see them before sending. Nothing is sent anywhere until you press Send. GitHub, as the host, processes standard server request data such as IP addresses for delivery and security; see GitHub’s privacy statement.
Children
LangBuddy is not directed at children under 13 and does not knowingly collect any information from them. Since the app collects no personal data at all, there is nothing held about any user of any age.
Your data, your control
- See it — everything the app holds is visible in the app itself.
- Take it — export your whole vocabulary to JSON, or to an Anki deck, from Settings.
- Delete it — delete individual entries in the app, or uninstall the app to remove everything, including backups and your stored API key.
Because we hold no data about you, there is nothing for us to hand over, correct or erase on request. Requests concerning data held by an AI provider must be made to that provider.
What might change, and what would not
Everything above describes the app as it is today: no account, no server, nothing of yours held anywhere but your own phone. Two things are being considered for later, and both would be optional:
- A hosted engine — translations and explanations from a service we run, for people who would rather not obtain an API key of their own.
- Hosted storage — a copy of your vocabulary kept for you, so a new phone can pick it up where the old one left off.
Either would need an account, and an account would need an email address — so either would mean we hold something about you for the first time. Two promises hold whatever happens: the device and your own API key stay first-class, so nothing hosted ever becomes the only way to use the app; and this page is updated before any of it ships, with what is collected, why, and how to get rid of it. Until you read that here, the answer is still no account and no server.
Changes
If this policy changes, the updated version will be posted here with a new date at the top. Material changes will also be noted in the app’s release notes.