Terms of Service

1. Agreement

These Terms of Service ("Terms") form a binding agreement between you ("you", "your", the "Customer") and the operator of zSender identified above ("zSender", "we", "us", "our"). By creating an account, accessing the dashboard, or sending through the API or SMTP relay, you accept these Terms. If you do not accept them, do not use the service.

These Terms incorporate the Acceptable Use Policy, the Privacy Policy, and, where you send personal data of individuals in the EEA or UK, the Data Processing Agreement. If you are accepting on behalf of an organisation, you confirm you have authority to bind it.

2. The service

zSender is a multi-tenant email service provider: a transactional and marketing email API, an SMTP relay, domain authentication (SPF, DKIM, return-path), delivery and engagement analytics, suppression management, inbound mail processing, and webhook delivery.

We may change, add, or remove features. Where a change materially reduces a core function you rely on, we will give reasonable notice; for security fixes, abuse response, and changes required by an upstream provider we may act immediately.

3. Accounts, eligibility and security

You must be at least 18 years old (or the age of majority where you live) and provide accurate registration information, including a working email address you control. One person or organisation may not operate multiple accounts to evade limits, quotas, or enforcement.

You are responsible for keeping your password, API keys, and SMTP credentials secure, and for all activity under your account, whether or not you authorised it. Tell us immediately at support@zsender.io if you suspect unauthorised use. API keys are shown once at creation and stored hashed: we cannot recover a lost key.

We require email verification before an account may add a domain, create an API key, or send live mail, and we may require additional verification where we suspect abuse.

4. Acceptable use

Your use of the service is governed by the Acceptable Use Policy, which is part of these Terms. In summary, and without limiting it: you may only email recipients who have given you provable consent or for whom you have another lawful basis; you must not send spam, phishing, malware, or unlawful content; you must honour unsubscribes immediately; and you must comply with applicable law, including GDPR, the ePrivacy rules, CAN-SPAM, CASL, and equivalent local anti-spam and data-protection legislation.

Breaching the AUP may result in immediate suspension or termination without notice and without refund. Because our sending infrastructure is shared between all customers, we enforce it strictly. See section 9.

5. Your content and your recipients

You retain ownership of everything you send through us ("Customer Content") and of your recipient lists. You grant us only the licence needed to operate the service: to transmit, store, process, scan for abuse and spam signals, and display your content back to you in the dashboard.

You are solely responsible for Customer Content and for your relationship with your recipients: for having a lawful basis to contact them, for the accuracy and legality of what you send, for any claims your messages make, and for handling their data protection requests. We do not review your content before it is sent and have no obligation to monitor it, though we may do so to enforce the AUP.

Where you send personal data through us we act as your processor and you act as the controller. See the Data Processing Agreement.

6. Plans, fees and payment

6.1 Plans

zSender offers a free plan and paid plans with the sending limits and monthly quotas described on our website. We may change plan features, limits and prices; price changes affecting an existing paid subscription take effect at the next renewal, and we will give notice before they do.

6.2 Payment

Paid plans are sold and billed through Polar, which acts as our merchant of record and as the seller for your purchase. Polar's own terms and refund policy apply to the payment transaction in addition to these Terms, and Polar handles invoicing and applicable sales tax or VAT.

Subscriptions renew automatically until cancelled. You may cancel at any time from your dashboard; access continues to the end of the paid period and no partial-period refund is given, except where a refund is required by applicable law or by Polar's policy. Failure to pay may result in downgrade or suspension.

6.3 Free plan

The free plan is provided without any warranty, service level, support commitment, or data retention guarantee. We may change, limit, suspend, or discontinue it, or terminate any free account, at any time, for any reason, without notice. Do not rely on the free plan for anything you cannot afford to lose.

7. Quotas, rate limits and fair use

Sending is subject to per-minute rate limits and monthly quotas by plan. We may apply additional throttling where sending patterns risk platform stability or deliverability. Attempting to circumvent a limit, including by opening additional accounts, is a breach of these Terms.

8. Availability and support

We aim to keep the service available and to give reasonable notice of planned maintenance, but we offer no uptime commitment and no service level agreement on any plan at this time. We may perform emergency maintenance without notice. Support is provided on a best-effort basis by email.

9. Deliverability and shared infrastructure

We do not and cannot guarantee that any message will be delivered, or that it will reach an inbox rather than a spam folder. Delivery depends on receiving mail providers, spam filters, blocklist operators, DNS, recipient configuration, and the content and reputation of your own sending: all of which are outside our control. Non-delivery, spam-folder placement, delay, filtering, and throttling by a receiving provider are not defects in the service.

zSender currently sends all customers' mail from shared IP addresses. You accept that another customer's sending behaviour, or a blocklisting event affecting shared infrastructure, may degrade or prevent delivery of your messages, and that this is not a breach of these Terms and gives no right to a refund, credit, or compensation. Equally, your own sending affects others, which is why we enforce the AUP strictly and immediately.

Third-party services in the delivery path (receiving mail providers, blocklists, DNS providers, and our hosting and payment providers) are not under our control and we accept no liability for their acts or omissions.

10. Disclaimer of warranties

To the fullest extent permitted by applicable law, the service is provided "as is" and "as available", and we disclaim all warranties, conditions and representations not expressly stated in these Terms, including any implied warranty of merchantability, satisfactory quality, fitness for a particular purpose, non-infringement, accuracy, or uninterrupted or error-free operation.

We do not warrant that the service will meet your requirements, that defects will be corrected, that the service will be secure or free of harmful components, or that any particular delivery, open, click, or deliverability outcome will be achieved.

11. Limitation of liability

To the fullest extent permitted by applicable law:

11.1 Excluded losses

We are not liable for any indirect, incidental, special, exemplary, punitive or consequential loss, nor for loss of profits, revenue, business, contracts, opportunity, anticipated savings, goodwill, reputation, or data, whether or not we were advised such loss was possible, and whether the claim arises in contract, tort (including negligence), or otherwise.

11.2 Cap

Our total aggregate liability arising out of or relating to the service and these Terms will not exceed the greater of (a) the total fees you actually paid us in the twelve (12) months immediately preceding the event giving rise to the claim, or (b) fifty euros (€50). Because the free plan involves no fees, our liability to a free-plan user is limited to (b).

11.3 What this does not limit

Nothing in these Terms excludes or limits our liability for death or personal injury caused by our negligence, for fraud or fraudulent misrepresentation, for gross negligence or wilful misconduct, or for any other liability that cannot lawfully be excluded or limited. If you are a consumer, nothing in these Terms affects your mandatory statutory rights, and any provision here applies only to the extent the law allows.

Each part of this section operates separately: if any exclusion or limit is held unenforceable, the remainder continues to apply.

12. Indemnity

You will defend, indemnify and hold us harmless from and against any third-party claim, demand, investigation or proceeding, and all resulting damages, fines, penalties, settlements, reasonable legal fees and costs, arising out of or relating to:

• Customer Content, or any message sent through your account;
• your breach of these Terms, the AUP, or the DPA;
• your violation of any applicable law, including anti-spam and data protection law, or of any third party's rights;
• your lack of a lawful basis or consent for contacting a recipient, or a claim brought by one of your recipients or by a supervisory authority in relation to them;
• use of your account by anyone, including through credentials you failed to secure.

We will notify you of any such claim, and you may not settle it in a way that imposes an obligation or admission on us without our written consent. This indemnity is not subject to the cap in section 11.2. If you are a consumer, this section applies only to the extent permitted by the law that protects you.

13. Suspension and termination

You may stop using the service and delete your account at any time. We may suspend or terminate your account, with or without notice, if you breach these Terms or the AUP, if your sending threatens the platform or other customers, if payment fails, if required by law, or, for free accounts, for any reason.

On termination your right to use the service ends immediately and we may delete your data, including sending history and suppression lists. Export anything you need beforehand. No refund is due on termination for breach. Sections 5, 9, 10, 11, 12, 14 and 15 survive termination.

14. Intellectual property

zSender, its software, design, documentation and branding remain our property or that of our licensors, and nothing in these Terms transfers any right in them beyond the limited right to use the service. You retain all rights in Customer Content. Any feedback you give us may be used without restriction or obligation.

15. Governing law and disputes

These Terms are governed by the laws of the Republic of Türkiye, without regard to its conflict-of-laws rules, and the parties submit to the exclusive jurisdiction of the courts of Türkiye.

If you are a consumer, this does not deprive you of the protection of mandatory provisions of the law of your country of residence, and you may bring proceedings in the courts of that country where the applicable law gives you that right. EU consumers may also use the European Commission's online dispute resolution platform.

16. Changes to these Terms

We may update these Terms. Material changes will be announced by email or in the dashboard before they take effect, and the "Last updated" date will change. Continuing to use the service after that means you accept the revised Terms; if you do not, stop using the service and cancel your subscription.

17. General

If any provision is held invalid or unenforceable, it is severed and the rest remains in force. Our failure to enforce a provision is not a waiver of it. You may not assign these Terms without our consent; we may assign them to a successor or to the company formed to operate zSender. These Terms, together with the AUP, Privacy Policy and DPA, are the entire agreement between us on this subject. Neither party is liable for failure to perform caused by events beyond its reasonable control.

18. Contact

Questions about these Terms: support@zsender.io. Abuse reports: abuse@zsender.io. Privacy requests: privacy@zsender.io.