Terms and conditions
As at 14 August 2026
These terms govern every contract for Mailwerk between Bartis.Dev, proprietor Darius Achilles, Goethestr. 30, 39397 Schwanebeck, Germany (the “provider”) and its customers.
The German version is the binding one. This English version is a translation provided for information.
1. Scope and contracting parties
(1) These terms govern the provision of the Mailwerk platform at cloud.mailwerk.app and the licensing of the Mailwerk Relay software.
(2) The contract is available only to businesses within the meaning of Section 14 of the German Civil Code, to legal entities under public law and to special funds under public law. No contract is formed with consumers.
(3) Differing or additional terms of the customer do not become part of the contract, even if the provider does not expressly object to them.
2. Formation of the contract and the account
(1) The contract is formed when an account is created on the platform. The provider may decline to create one without giving reasons.
(2) The customer keeps its details current, in particular its billing address and a working email address.
(3) Credentials are confidential. Two-factor authentication is mandatory for accounts with owner rights. The customer notifies the provider without undue delay if it suspects misuse of its account.
3. What is provided
(1) The provider makes available a platform in which the customer manages its end customers, their sites and the agents running there, enrols agents, configures them and sees their operating state.
(2) Mailwerk Relay is software the customer runs on the network of each of its end customers. It accepts messages over SMTP from devices and applications and hands them to that same end customer's Microsoft 365 tenant through Microsoft's interface.
(3) Message contents are not transferred to the provider's infrastructure in the process.
(4) The scope owed follows from the product description on mailwerk.app in the version current when the contract is formed.
4. Boundaries, no delivery guarantee
(1) Messages are delivered by Microsoft. The provider owes neither delivery nor delivery success and has no influence over whether receiving systems accept a message.
(2) Operation requires a working Microsoft 365 tenant belonging to the end customer, an app registration with the documented permissions, and a suitable machine on the end customer's network. Those prerequisites are the customer's responsibility.
(3) Changes to third-party services, in particular to Microsoft 365, are outside the provider's control. The provider adapts its service to a reasonable extent but does not owe any particular functionality of a third-party service.
5. Prices, free sites, bands
(1) The unit of billing is one site per calendar month. A site is one location of an end customer with an agent running there.
(2) Two sites per account are free of charge. From the third site on, every site on the account is billed, the first two included. The free sites are not limited in time.
(3) The price per site depends on the total number of sites on the account and then applies to each one of them: 1 to 49 sites 10 euros, 50 to 199 sites 8 euros, 200 sites and up 6 euros, in each case per site per month.
(4) White label is billed at 99 euros per account per month, regardless of the number of sites.
(5) No VAT is charged or shown, under Section 19 of the German VAT Act. The amounts stated are therefore the amounts invoiced. Should that exemption cease to apply, statutory VAT is added; the provider gives at least six weeks' notice of this in text form.
(6) The provider may change prices on six weeks' notice to the end of a month. Clause 17 applies accordingly.
6. Invoicing and payment
(1) Billing is monthly in arrears, based on the number of sites held during the billing period. Invoices are made available electronically.
(2) A site added during a billing period is billed pro rata from the day it is created. When a site is removed, billing ends with the current billing period; no refund is made for the part-period.
(3) Payment is taken using the payment method held on the account. The provider uses a payment service provider for this.
(4) Clause 13 applies where payment is late.
7. Term and termination
(1) The contract runs for an indefinite period. Either side may terminate it on one day's notice to the end of the current billing period, in text form or through the platform.
(2) The customer may remove individual sites at any time. The remaining sites are unaffected.
(3) The right of either side to terminate for good cause is unaffected. Good cause for the provider includes in particular a serious breach of clause 10.
(4) The data processing agreement governs what happens to data after the contract ends.
8. Availability and maintenance
(1) The provider operates the platform with the care of a prudent business. No particular level of availability is promised; there is no service level agreement.
(2) The provider announces maintenance in advance where possible and schedules it outside busy hours where it can.
(3) Delivery by the agent does not depend on the platform being reachable. While the platform is unreachable, remote administration and the enrolment of further sites are unavailable; within its valid operating licence the agent keeps delivering.
9. The customer's obligations
(1) The customer runs its own infrastructure and the infrastructure deployed at its end customers on its own responsibility, including network connectivity, operating system and backups.
(2) The customer creates the app registration in its end customer's tenant and obtains the end customer's consent for it.
(3) The customer ensures that it is entitled, as against its end customers, to involve the provider as a service provider, and that the data protection requirements for doing so are met.
(4) The customer keeps the deployed agents current. The provider may specify a minimum version and, on reasonable notice, require its use where this is necessary for security or operation.
10. Acceptable use
(1) Mailwerk is for sending operational messages from devices and applications, such as system notices, alerts, scans and documents.
(2) The following are prohibited in particular:
(3) On reasonable suspicion of a breach the provider may throttle or suspend individual sites and ask the customer to comment. Clause 13(3) is unaffected.
(4) The customer remains responsible for the messages sent through its sites. It indemnifies the provider against third-party claims arising from a breach of this clause, to the extent the customer is responsible for the breach.
- sending unsolicited bulk advertising, and sending to addresses for which there is no consent or other legal basis,
- sending with forged or unauthorised sender details,
- sending unlawful content,
- circumventing the limits set by the end customer's Microsoft 365 tenant,
- passing credentials to third parties outside the customer's own company.
11. Rights in the software
(1) For the term of the contract the customer receives a simple, non-exclusive, non-transferable right to use the platform and to run Mailwerk Relay in the manner provided for in this contract.
(2) The customer may use the service as part of its own service to its end customers. Reselling it as a standalone product outside such a service requires a separate agreement.
(3) The software may not be reverse-engineered beyond what statute permits, in particular Section 69e of the German Copyright Act.
(4) With white label the customer receives the right to place its own branding on the agent's local interface and on the output the platform addresses to its end customers. Rights in the “Mailwerk” name remain with the provider.
12. Running it on your own infrastructure
(1) By separate agreement the customer may run the platform on its own infrastructure.
(2) The fee is agreed individually and invoiced annually in advance.
(3) Included are the licence for the agreed term, updates and a named contact. Running the installation, including servers, backups and availability, is the customer's responsibility.
(4) The installation checks its licence against mailwerk.app at regular intervals. If the agreed term ends without being renewed, the right of use ends.
13. Late payment, throttling, suspension
(1) If the customer is late in paying, the provider issues a reminder in text form with a 14-day deadline.
(2) If payment is still not made, remote administration and the enrolment of further sites cease first. After that the provider may throttle existing agents. The provider does not switch delivery off entirely because of late payment.
(3) In the event of a serious breach of clause 10, a threat to operations, or an order by a public authority, the provider may suspend the affected sites without prior notice. It informs the customer without undue delay.
14. Data protection
(1) Where the provider processes personal data on the customer's behalf under this contract, the data processing agreement concluded together with this contract applies.
(2) On questions of processing on the customer's behalf, the data processing agreement takes precedence over these terms.
15. Confidentiality
(1) Each side keeps the other side's confidential information confidential and uses it only for the purposes of this contract.
(2) This does not cover information that is public, becomes public without a breach of this obligation, was developed independently, or must be disclosed under a legal or official obligation.
(3) The obligation continues for three years after the contract ends.
16. Liability and limitation period
(1) The provider is liable without limit for intent and gross negligence, for injury to life, body or health, to the extent of any guarantee given, and under the German Product Liability Act.
(2) For ordinary negligence the provider is liable only for breach of a material contractual obligation, that is, an obligation whose fulfilment makes proper performance of the contract possible in the first place and on whose observance the customer may regularly rely. In that case liability is limited to the foreseeable damage typical of this kind of contract.
(3) Liability under paragraph 2 is capped at the fees the customer owed for the twelve months before the damaging event; where the contract ran for less than that, the fees owed for twelve months apply. For all damaging events in a contract year taken together, liability under paragraph 2 is capped at 5,000 euros.
(4) For as long as the customer owes no fees under clause 5, the provider supplies the service free of charge. For damage arising in that period the provider is liable only under paragraph 1; there is no liability for ordinary negligence.
(5) For loss of data the provider is liable under paragraphs 1 to 4 only for the effort that would have been required for recovery had the customer kept proper and regular backups.
(6) The provider is not liable for delivery by Microsoft, for faults on the network of the customer or its end customers, or for the consequences of changes to third-party services.
(7) The customer backs up its email data independently of this service and archives it where required to do so. Where it does not, any claim for damages is reduced accordingly under section 254 of the German Civil Code.
(8) Claims by the customer against the provider become time-barred twelve months after the statutory limitation period begins. This does not apply to claims under paragraph 1, nor to claims for a defect the provider fraudulently concealed; for those the statutory periods remain.
(9) Paragraphs 1 to 8 also apply for the benefit of the provider's legal representatives, employees and subcontractors.
17. Changes to these terms
(1) The provider may change these terms where this is necessary to reflect a change in the law, in case law or in the service, and where the change does not unreasonably disadvantage the customer.
(2) Changes are announced to the customer in text form at least six weeks before they take effect. If the customer does not object before they take effect, they are deemed accepted. The provider points this out separately in the announcement, together with the right to object.
(3) If the customer objects, either side may terminate the contract with effect from the date the change would take effect.
18. Final provisions
(1) German law applies, excluding the UN Convention on Contracts for the International Sale of Goods.
(2) If the customer is a merchant, a legal entity under public law or a special fund under public law, the provider's registered seat is the exclusive place of jurisdiction.
(3) Declarations under this contract require text form unless stated otherwise.
(4) The customer may set off only against claims that are undisputed or have been finally determined by a court.
(5) The customer may transfer this contract to a third party only with the provider's consent.
(6) If a provision is invalid, the rest of the contract remains in force.
The data processing agreement under Article 28 GDPR has a page of its own: Data processing
We answer questions about this using the contact details in the imprint.