Acceptable Use Policy

Deliverability is a shared resource. When one sender abuses it, mailboxes penalize the sending infrastructure and everyone's mail suffers. This policy keeps mailstein a place your important email actually reaches the inbox. It applies to everyone who sends through mailstein.

1. Send only to people who want it

• Only send to recipients who have given you permission (signed up, purchased, or otherwise opted in). No purchased, scraped, rented or harvested lists.
• Every marketing/broadcast email must include a clear, working unsubscribe, and you must honor opt-outs promptly.
• Make it clear who the mail is from; don't forge headers or use misleading subject lines.

2. Prohibited content and behavior

• Spam — unsolicited bulk email of any kind.
• Phishing, spoofing, or fraud — impersonating others or deceiving recipients.
• Malware — viruses, ransomware, or links to malicious content.
• Illegal content, harassment, hate, or content that violates others' rights.
• Certain high-abuse categories are not permitted without prior approval (e.g. unsolicited affiliate/lead-gen blasts, "get rich quick", most crypto/ICO promotion, illegal pharma, gambling where prohibited).
• Sending on behalf of a third party without authorization, or reselling access to evade limits.

3. List hygiene & reputation

• Keep your bounce and complaint rates low. Sustained high bounces or spam complaints can get your sending paused — this protects you and the platform.
• Respect the suppression list: we automatically suppress hard bounces and complaints, and you must not attempt to circumvent it.
• Warm up new volume gradually and send consistently; don't dump a huge cold list on day one.

4. Technical fair use

• Don't exceed your rate/volume limits or try to bypass them with multiple accounts.
• Don't probe, overload, or attempt to disrupt the service or its infrastructure.
• Keep your API keys secure; you're responsible for traffic sent with them.

5. Enforcement

We monitor for abuse and complaint signals. Depending on severity we may throttle sending, require remediation, suspend, or terminate an account — and, for serious or ongoing abuse, do so immediately and without notice to protect other senders. We may report unlawful activity to the appropriate authorities.

6. Reporting abuse

If you received unwanted mail sent through mailstein, or want to report a violation, contact abuse@mailstein.com. We take reports seriously.