Privacy Policy
Last updated: October 5, 2026
Overview
Sokolov Systems operates the Email Provider Filter at sokolovsystems.online. This Privacy Policy explains what data we collect, how we use it, and what we do not do with it.
What Data We Process
When you use the Email Provider Filter, you submit email addresses for validation and provider identification. We process these email addresses to:
- Validate email syntax (check that the address is structurally correct).
- Extract the domain portion of each email address.
- Query public DNS records (MX and SPF/TXT) for each unique domain.
- Match DNS results against known provider signatures.
- Group and sort results by provider for display and export.
What We Do Not Do
- We do not store submitted email addresses permanently. Email addresses are processed in memory for the duration of the request and are not persisted to a database.
- We do not send test emails to the addresses you submit.
- We do not attempt to access mailboxes or verify that a specific mailbox exists.
- We do not sell, share, or transfer submitted email addresses to third parties.
- We do not use submitted email addresses for marketing.
DNS Lookups
The tool queries public DNS infrastructure (via DNS-over-HTTPS to Google's public DNS resolver) to retrieve MX and TXT records for the domains in your submission. These are the same DNS records that are publicly available to anyone. The DNS queries include only domain names, not full email addresses.
Telegram Integration
The tool includes a Telegram channel gate for exporting results. Clicking "Join Telegram" opens a Telegram invite link in a new tab. We do not receive any data from Telegram about whether you joined. The verification is client-side only — once you click the join button, the export buttons are enabled in your browser.
Cookies and Local Storage
The Email Provider Filter does not use cookies. The tool does not use local storage or session storage to persist data. All state is in-memory and cleared when you close or refresh the page.
Analytics
We do not currently run third-party analytics on the Email Provider Filter. If analytics are added in the future, this policy will be updated.
Third-Party Services
- Google Public DNS — used for DNS-over-HTTPS lookups. Only domain names are sent to Google's DNS resolver. See Google Public DNS Privacy.
- Supabase — used as the serverless backend for the validation API. Email addresses are sent to our Supabase Edge Function for processing and are not stored in any database table.
Your Rights
Since we do not persist submitted email addresses, there is no stored data to access, modify, or delete. If you have questions about this policy, contact us.
Children's Privacy
The Email Provider Filter is not directed at children under 13. We do not knowingly collect any data from children.
Changes to This Policy
We may update this Privacy Policy from time to time. Changes will be posted on this page with an updated date.
Contact
If you have questions about this Privacy Policy, please contact Sokolov Systems.