Dia.best Privacy Policy
Last updated: September 1, 2026.
This policy describes how Dia.best processes data across the web service, Android application, Wear OS functionality and widgets.
Dia.best is designed to work with information related to diabetes management. Some of the information processed by the service is therefore sensitive health-related data.
1. Data we process
Account and authentication data:
- email address;
- OAuth provider identifiers when an external sign-in provider is used;
- authentication sessions and technical sign-in information.
Health and therapy data:
- glucose values, measurement times, direction and rate of change;
- insulin, bolus and active-insulin information;
- carbohydrates, meals and journal entries;
- therapy parameters, targets, ratios and insulin sensitivity;
- selected insulin types and insulin parameters;
- sensor, pump and related event information;
- calculation, analysis and personalized recommendation results.
Nightscout:
- Nightscout server address;
- token or other access credentials supplied or generated for the user;
- glucose data and treatments obtained from Nightscout where required for Dia.best functionality;
- technical information required to provision and connect a Dia.best hosted Free Nightscout instance.
Photos and AI features:
- food photographs uploaded by the user;
- photo-analysis results and estimated food composition;
- messages submitted to AI-powered features;
- AI responses, reports and analysis results.
Technical data:
- IP address and User-Agent;
- application version and device model;
- connection status and background application status;
- permission, notification and battery-optimization status;
- cookies and session identifiers.
Payments and partner program:
- payment identifier, amount, status and confirmation of credit;
- service balance;
- partner reward and withdrawal-request data.
Requests for connection assistance:
- name and telephone number when voluntarily provided by the user;
- sensor model, phone type, application used and Nightscout status;
- IP address and User-Agent for abuse prevention and request processing.
2. How the data is used
- to create and authenticate an account;
- to connect to Nightscout and synchronize data;
- to display glucose, therapy, carbohydrates and related information;
- to perform calculations, forecasts, recommendations and historical analysis;
- to provide AI functionality and analyze food photographs;
- to operate the Android application, Wear OS functionality and widgets;
- to process payments for paid service functions and maintain account balances;
- to operate the partner program;
- to diagnose errors, protect security and prevent abuse;
- to provide user support.
3. Data shared with other services
Dia.best shares data with third parties only to the extent required to provide the relevant functionality.
- Nightscout. Dia.best may communicate with the Nightscout instance connected to the user's account in order to read or write authorized data.
- OAuth providers. When external sign-in is used, the selected provider participates in the authentication process.
- AI providers. When AI-powered features are used, data required for the request, including health-related information or photographs selected by the user, may be transmitted to AI-processing providers used by Dia.best.
- Payment providers. When a payment is made, information necessary to process and confirm the payment is transmitted to the payment system used by Dia.best.
- Technical infrastructure. Data may be processed by server, network and other infrastructure providers to the extent necessary to operate Dia.best.
4. Storage and security
Data is retained for as long as necessary to operate an active account and provide Dia.best functionality.
Technical and organizational measures are used to protect information, including access controls and HTTPS connections to Dia.best. No method of storage or transmission can guarantee absolute security.
5. Account and data deletion
A user can request account deletion through Profile → Delete account. The public account-deletion page is available at dia.best/en/delete-account.
When deletion is confirmed, Dia.best deletes, among other things:
- active sessions and OAuth links;
- sign-in data;
- Nightscout URL and access credentials stored by Dia.best;
- locally stored glucose and therapy data;
- journal, nutrition and medical-profile settings;
- AI messages, analyses and reports;
- uploaded food photographs;
- local caches and other medical-profile data.
For an externally hosted Nightscout instance, deleting the Dia.best account does not delete the original data from that external Nightscout server. Dia.best removes its connection, stored access information and local copies.
Minimal records of completed payments and financial transactions may be retained after account deletion where required for accounting, fraud prevention, dispute resolution or compliance with applicable legal requirements. Such records are minimized and are not used as an active medical profile.
6. Managing your data
A user can:
- disconnect Nightscout;
- change available profile and therapy settings;
- delete the account and associated data;
- contact support regarding data processing.
7. Changes to this policy
This policy may be updated when Dia.best functionality, technologies or legal requirements change. The current version is published on this page.
8. Contact
Service and application: Dia.best
Privacy and data-deletion questions:
@dia_best