JstSync is an app for Android phones and a desktop app for computers. It copies files from folders you choose on your phone to your own computer, over your local Wi‑Fi. This policy covers the Android app and says what it uses, what leaves your phone and where it goes.
The short version: your files go from your phone to your own computer and nowhere else. The only thing the developer can ever receive is a crash report that you choose to send.
The developer is Maksim Pashkov. Contact: mpashkov.work@gmail.com.
What the app uses, and why
- Folders you choose. You choose folders through Android’s own folder picker. JstSync reads the files in them, and only reads: it never changes or deletes anything on your phone. It keeps Android’s permission to read those folders until you stop using them. It has no access to your other files.
- Camera. Only while the scanner screen is open, to read the QR code that the desktop app shows. The pictures are processed on the phone to read the code. They are never stored, saved or sent. You can also paste the code instead.
- Devices on the local network. To reach your computer and to find it again when its address changes. On Android 17 and later the system asks for this permission before pairing. The app listens for the announcement of your own computer on your Wi‑Fi and sends a standard network query; it accepts an answer only from the computer you paired with.
- Notifications. For the notification that shows a transfer in progress when you leave the app, with its Stop button. The app explains this before the system asks, and works without it.
- Background work. The app runs a short check about every 15 minutes or later, on an unmetered Wi‑Fi, to send new files, and keeps working in a foreground service while a transfer goes on after you left the app. It uses the permissions to run at boot (so the check continues after a restart) and to keep the phone awake while it works.
- The network. The app connects to the computer you paired with and, only when you tap Send on a crash report, to the developer’s crash-report server (see “Crash reports” below). It connects to nothing else.
What leaves your phone, and where it goes
Apart from a crash report that you choose to send (see “Crash reports” below), only to the computer you paired with, on the same network, over an encrypted connection (TLS) that only your phone and that computer can use: the phone checks the computer’s certificate, and the computer checks the phone’s.
- The files in the folders you chose, copied exactly as they are (so anything inside a file, such as the location in a photo, goes along), with their names, the folders they are in, their sizes, dates and checksums.
- When you pair, and later: the name of your phone, its model, its Android version and whether it is a tablet, so that the computer can show the phone in its list.
- The “Send a test file” button (Just test) sends one small text file that the app makes up.
Nothing goes to any third party, and nothing goes to the developer unless you tap Send on a crash report. The developer cannot see your files, your computer or your phone. The app has no account, no advertising and no usage analytics or tracking, and it does not use the advertising ID. It does not read your location, contacts or messages.
Crash reports
If JstSync closes because of an error, the app asks you the next time you open it whether to send a crash report to the developer, with a box for an optional comment. Nothing is sent unless you tap Send. If you tap Don’t send, the report is deleted from your phone. If you close the question some other way, the report stays on the phone and the app asks again the next time it starts. If several reports are waiting (the app keeps the newest three), one question covers all of them.
- What a report holds. The technical details of the error (the stack trace), which in rare cases may contain a file or folder name, because the app cannot clean them; the app version, the Android version and the phone model; the time of the crash, with the phone’s time-zone offset; your comment, if you wrote one (up to 500 characters); and the end of the app’s own diagnostic log (at most the last 1 MiB), which is written without file, folder or device names or addresses.
- Two random IDs. A random ID of this installation, made by the app on the phone, so that reports from one phone can be told apart from those of another; it is not your Android ID, your advertising ID or any number of your phone, and it is deleted with the app’s data. And a random ID of each report, so that a report sent twice is counted once.
- Nothing else. No files, photos, folder lists, computer names, addresses, location, contacts or messages, and no system log of the phone.
- Where it goes. Over an encrypted connection (HTTPS) to a server that the developer runs, at the address of this website. It is not shared with anyone and is used only to find and fix the error.
- How long it is kept. At most 90 days after the crash, plus up to one day until the daily automatic deletion. A report that could not be sent, for example without a connection, waits on the phone and is sent the next time the app starts; the phone deletes a waiting report after 90 days.
- The server and your address. While it receives a report, the server sees the network address your phone connects from, as every server does. It uses the address only in its memory, to accept at most one report an hour from one address and at most 60 reports an hour in total, and it does not store it with the report or write it to a log. A report over a limit stays on the phone and is sent at a later start.
- The basis and your rights. Your consent (Art. 6(1)(a) GDPR), given separately for each report by tapping Send. You can refuse by tapping Don’t send. A report that has been sent can be deleted on request: write to the contact address below, with the date of the crash and the model of your phone, which is how it is found.
What is stored on your phone
In the app’s private storage: the pairing (your computer’s name, its address and port, and the fingerprint of its certificate; the phone’s key is kept in the Android Keystore), the list of folders you chose, an index of the files found in them and which ones were sent, and whether you pressed Stop. The app also keeps its own diagnostic log of the last three days (no names, paths, addresses or file names), in its private storage, and sends it only as part of a crash report that you choose to send. If the app has crashed, it also keeps the random installation ID and the crash reports that wait for your answer or for a connection (see “Crash reports”). The log, the installation ID and the waiting reports are excluded from Android’s cloud backup and from device transfer. Nothing else is stored.
Your choices and deleting data
- You choose which folders are copied, and you can stop at any time with Stop, or remove a folder.
- You can remove the phone in the desktop app, or uninstall JstSync, or clear its storage in Android’s settings: that deletes everything the app stores on the phone. The files already copied to your computer are yours and stay there until you delete them.
- The developer holds only the crash reports that you chose to send, and deletes each automatically after at most 90 days. To have one deleted sooner, write to the contact address (see “Crash reports”).
Age signals from Google Play
On Google Play, the app asks Google Play, once each time it starts, for the age range Google Play holds for the account (Google Play may ask you first whether to share it). When that range is under 13, the app shows “JstSync is not available” and does not pair, sync, run in the background or ask to send crash reports on the phone. Any other answer, or none, changes nothing. The app reads the range on the phone only, keeps it in memory while it runs, does not store it and sends it nowhere.
Children
JstSync is meant for people aged 13 and older. It is not directed at children under 13, and it collects nothing from anyone except the crash reports that a user chooses to send. It never asks a user whom Google Play reports as under 13 to send one.
Changes to this policy
If the app changes in a way that changes this policy, the new text is published on this page and the date above changes. Changes that collect more would need a new version of the app and an updated Data safety section on Google Play.