Acceptable Use Policy

1. Scope

This Acceptable Use Policy ("AUP") applies to everyone who uses zSender, including on the free plan, and forms part of the Terms of Service. Capitalised terms not defined here have the meaning given in the Terms.

You are responsible for all use of your account, including use by your employees, contractors, end users, and anyone using your API keys or SMTP credentials, whether or not you authorised it. Keeping your credentials secure is your obligation, and a compromised key does not transfer responsibility to us.

2. Consent: the core rule

You may only send email to recipients who have given you clear, explicit and provable consent to receive it, or to whom you have another lawful basis to send (for example a genuine transactional message arising from a transaction the recipient initiated).

2.1 What counts as consent

• An opt-in the recipient took deliberately, never a pre-ticked box.
• Consent obtained for your messages, at the time of collection, with the topic described clearly.
• A record of when and how each address was collected, which you must be able to produce on request.

2.2 What never counts as consent

• Purchased, rented, scraped, appended, or otherwise third-party-sourced lists.
• Addresses harvested from websites, directories, social networks, or WHOIS records.
• Consent given to a different sender, a previous owner of a domain or brand, or an affiliate.
• Inferred consent from a business-card exchange, a conference badge scan, or silence.

Proof of consent must be provided within 3 business days of our request during an abuse investigation. Inability to produce it is itself a breach of this AUP, and we may suspend sending until it is produced.

3. Prohibited content and activity

You must not use zSender to send, host, or link to:

• Phishing, credential harvesting, or impersonation of any person, brand, payment provider, government body, or platform, including messages designed to look like they come from someone else.
• Malware, ransomware, spyware, or links to any of the above.
• Content that is unlawful, defamatory, harassing, threatening, or that infringes another party's intellectual property or privacy rights.
• Child sexual abuse material, non-consensual sexual content, or content sexualising minors: accounts doing this are terminated immediately and reported to authorities.
• Content promoting violence, terrorism, or hatred against a protected group.
• Chain letters, pyramid or Ponzi schemes, multi-level marketing recruitment, "get rich quick" offers, and deceptive affiliate marketing.
• Cryptocurrency airdrops, token pre-sales, trading signals, and unlicensed financial or investment advice.
• Payday loans, debt relief or credit repair offers, and unlicensed gambling.
• Prescription pharmaceuticals, controlled substances, or health products making unsubstantiated medical claims.
• Deceptive headers, forged sender addresses, misleading subject lines, or an unrelated reply-to designed to hide who is sending.

We may decline or discontinue service to any category of sender at our discretion, including categories not listed above, where we judge the deliverability or legal risk to be disproportionate.

4. Technical and security rules

• Only send from domains you control and have verified in your account. Verification exists to prove control: circumventing it is a breach.
• Do not attempt to bypass rate limits, quotas, the suppression list, or any abuse control, including by creating multiple accounts.
• Do not probe, scan, or test the vulnerability of our systems without our prior written permission, and do not attempt to access another customer's data.
• Do not resell, sublicense, or provide the service to third parties as your own sending infrastructure without our written agreement.
• Do not use the service to operate an open relay, or to send on behalf of a party whose identity you cannot disclose to us on request.

5. Deliverability thresholds

Because sending reputation is shared (see Section 6), we monitor these rates per account. Exceeding them may trigger throttling, suspension, or termination without prior notice:

These are ceilings, not targets. A campaign well under every threshold can still be suspended if it draws blocklist attention, provider feedback, or complaints that put other customers at risk.

6. Shared sending infrastructure

zSender currently delivers all customers' mail from shared IP addresses. This has two consequences you must understand and accept before using the service:

• Your sending affects others. Spam, phishing, or high complaint rates from your account can cause the shared IP to be blocklisted, degrading delivery for every other customer. This is why our enforcement is immediate and why we do not negotiate over the thresholds above.
• Others' sending can affect you. Another customer's behaviour, or a blocklisting event outside our control, may delay or prevent delivery of your messages. We work to prevent this, but we do not warrant sending reputation or deliverability, and a reputation-driven delivery failure is not a service defect, a breach of these terms, or grounds for a refund or credit. See sections 9 and 11 of the Terms of Service.

If your use case cannot tolerate shared reputation, this service is not currently suitable for it.

7. Unsubscribe and complaint handling

• Every marketing message must contain a clear, working, one-click unsubscribe. We inject standards-compliant List-Unsubscribe headers, but that does not replace a visible unsubscribe link in your content.
• Unsubscribe requests must be honoured immediately and permanently. Our suppression list does this automatically; you must not send around it, re-import a suppressed address, or move it to another account.
• Hard bounces and spam complaints are added to your suppression list automatically. You may remove an entry only if you can evidence that doing so is lawful and consented.

8. Enforcement

We may take any of the following actions, with or without prior notice, where we reasonably believe this AUP has been or is about to be breached, or where sending from your account threatens the platform's reputation or other customers:

• Throttle or pause sending on your account.
• Block specific messages, recipients, domains, or content.
• Suspend your account and revoke API keys.
• Terminate your account and delete its data.
• Report the activity to law enforcement, anti-abuse organisations, blocklist operators, or affected third parties, and disclose the information necessary to do so.

No service credit, refund, or compensation is available for any interruption resulting from enforcement of this AUP. Where circumstances allow we will tell you what happened and what is needed to restore service, but we are not obliged to give advance notice: an abuse wave measured in minutes cannot wait for a notice period.

Enforcement decisions are ours to make on the information available at the time. We may act on a reasonable belief; we are not required to prove a breach before acting to protect the platform.

9. Reporting abuse

If you have received mail sent through zSender that you believe breaches this policy, report it to abuse@zsender.io. Include the full message headers where possible: they let us identify the sending account. We investigate every report and act where a breach is found.

10. Changes

We may update this AUP as abuse patterns and provider requirements change. Material changes will be announced and the "Last updated" date revised. Continuing to use the service after a change means you accept the updated policy.