1. What MailProbe is
MailProbe is a diagnostic tool that opens a real TCP connection to a mail server you specify, reads the SMTP greeting banner, sends an EHLO command, and reports the capabilities the server advertises. It is not an email service, a message store, or a communications platform.
2. What data we process
When you use the MailProbe app at /app, we process the following data:
- The hostname you type — the mail server hostname (e.g. mx.example.com) and port you select (25, 465, or 587). This is sent from your browser to our Cloudflare Worker, which proxies it to our backend droplet for the probe request.
- Your IP address — collected automatically by our Cloudflare Worker and backend droplet as part of standard HTTP request handling. We do not log or store IP addresses beyond ephemeral connection metadata.
- Probe results — the SMTP banner, EHLO capability list, handshake timing, and raw exchange log returned by the target server. These results are returned to your browser only. They are not stored, logged, or persisted on any server.
3. What we do NOT collect
MailProbe does NOT:
- Use cookies, tracking pixels, or browser fingerprinting
- Include analytics scripts (Google Analytics, Facebook Pixel, or similar)
- Collect your email address, name, or any personal identifier
- Store probe results on any server
- Share data with third parties
- Process payment information (the demo checkout on the pricing page is entirely client-side JavaScript with no data transmitted)
4. How data is transmitted
All communication between your browser and our infrastructure is over HTTPS. The flow is:
- Your browser sends the hostname and port to the Cloudflare Worker via a GET request to
/api/probe - The Worker proxies the request to our backend droplet
- The droplet opens a TCP connection to the target mail server and returns the probe results
- Results are delivered to your browser and displayed on the page
- Results are discarded when you reload or navigate away
5. Legal bases (GDPR Art. 6)
We process hostname and IP data based on our legitimate interest in operating a diagnostic tool (Art. 6(1)(f)). The processing is minimal, necessary to fulfill your request, and does not involve profiling, retention, or onward transfer.
6. Data retention
We maintain no databases, logs, or caches of probe results. IP addresses appearing in standard HTTP server logs are retained for no longer than 14 days for operational security purposes (rate-limiting and abuse detection) and are then automatically rotated.
7. Your rights
Under the General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA), you have the right to:
- Request access to any personal data we hold about you
- Request deletion of your personal data
- Object to processing of your personal data
- Withdraw consent where processing is based on consent
- Lodge a complaint with your local data protection authority
Because we do not store personal data, exercising these rights will typically result in confirmation that no data is held. Contact us at the address below with any questions.
8. Contact
For privacy-related inquiries, contact: privacy@mailprobe.app
This policy may be updated occasionally. The "Last updated" date at the top of this page indicates when it was last revised.