Last updated: 25 October 2026
This policy explains how Beli Grad Studio (Sergei Sokolov PR Racunarsko programiranje Beograd, Belgrade, Serbia) handles data in its mobile apps, including the DTZ speaking trainer.
What data we process
Your voice during a practice exam. It is streamed in real time to our AI provider to run the conversation, recognize speech and evaluate your answers.
Text transcripts of the exam, your scores and the feedback generated for you.
A random app ID created when you first open the app (not your name or Google account), your balance of exams and the records of your purchases in the app (Google Play order number, product, date).
Basic technical data: app version, device model, operating system version and error logs.
To prevent abuse of the free exam, a hashed form of your network address for up to 2 days.
We do not ask for your name, contacts, location or photos. We do not show ads and we do not sell your data.
Why we process it
Only to run the practice exam, give you feedback, keep your balance of bought exams, prevent abuse, fix errors and improve the app.
Service providers
OpenAI (USA): real-time voice conversation, speech recognition and evaluation.
Anthropic (USA): may be used to write the final feedback text.
Google (USA): app distribution and payments through Google Play.
Cloudflare (USA, servers worldwide): hosting of our app server and database.
These providers process data under their own terms. Under their API terms, OpenAI and Anthropic do not use this data to train their models by default.
Storage
We do not store audio recordings on our servers. Transcripts, scores and error logs are kept for up to 30 days to fix problems and are then deleted. Your balance of exams and your purchase records are kept as long as you use the app, so that bought exams are not lost. The hashed network address is deleted after 2 days.
How to delete your data
Step one: send an e-mail to sokolovsergei200219@gmail.com with the subject "Delete my data".
Step two: add the Google Play order number of one of your purchases (from the Google Play receipt e-mail) or the date and time of your exams, so that we can find your data.
Step three: we delete your balance, purchase records and any remaining transcripts within 30 days and confirm by e-mail. Bought but unused exams are lost after deletion.
Uninstalling the app deletes all data stored on your phone. Exam transcripts are deleted automatically after 30 days in any case.
Your rights
You can ask us to delete your data or to send you a copy at any time by writing to the e-mail below. If you are in the EU or EEA, you have the rights of access, correction, deletion, restriction and objection under the GDPR, and you can complain to your local data protection authority.
Children
Our apps are not intended for children under 16.
Changes
If this policy changes, we will update this page and the date above.
Contact
sokolovsergei200219@gmail.com