Terms of Use

Last updated: November 2026

1. Scope and provider

These terms govern the use of Kayio – the web application at kayio.app, the Kayio apps for Android and iOS and the Kayio add-on for Gmail (together "Kayio" or "the service").

The provider is Shahab Hassani-Müller, Försterweg 167, 22525 Hamburg, Germany (see the Impressum). Kayio is operated as a sole proprietorship.

Kayio is intended for consumers. You must be of legal age to use it. These terms apply in their German version; translations are provided for convenience and the German version prevails in case of discrepancies.

2. What Kayio does

Kayio helps you keep purchases and receipts in order and keep track of deadlines. This includes in particular:

• filing purchases from receipt photos, PDF invoices, forwarded order emails, the Gmail add-on or manual entry
• automatic recognition of retailer, item, price, purchase date and further details
• calculation of the statutory warranty period for the market you selected and display of return deadlines
• reminders by email and push notification before deadlines run out
• export of warranty documents
• the family vault (section 5)

Using Kayio is free of charge and not limited in time. Additional Premium features may be offered for a fee (section 8).

3. No legal advice, estimates and automatic recognition

Kayio is an organisational tool, not legal advice. Whether you have a right of return, withdrawal or warranty in a given case depends solely on the law and the terms of the retailer or manufacturer concerned.

Kayio adopts return deadlines when they are stated on the receipt or in the order email. Where no such statement exists, Kayio shows an estimate taken from a table of retailer return policies that we maintain. Estimates are marked as such in the app and may be outdated or inapplicable to your purchase. Warranty periods are calculated according to the statutory default of your market and may differ in individual cases, for example for second-hand goods, manufacturer guarantees or purchases made as a business.

Automatic recognition may be incorrect or incomplete. Kayio prefers to leave a field blank rather than guess. You are responsible for checking and correcting recognised details, in particular dates and deadlines. Reminders may fail to arrive, for example due to technical faults, spam filters or device settings. Meeting deadlines remains your responsibility.

4. Account

You need an account to use Kayio. You sign in with your email address using a sign-in code or link delivered by email, or alternatively with your Google or Apple account. There is no password. Please therefore protect access to your mailbox and your devices; actions taken through your account are attributed to you insofar as you are responsible for them.

Each person may keep only one account for themselves. You may use Kayio only for your own purchases and receipts or for those you are entitled to file.

5. Family vault

You can invite up to four other adults into your vault. Each member uses their own account. The following applies to the family vault:

• Members see each other's sign-in email address and all shared purchases in the vault, including receipts, order emails, invoices and return documents. Every member can edit and delete shared purchases and receives the reminders for them.
• Every purchase is either shared or private. Private purchases are visible only to the person who filed them; only that person can change the marking. When joining, you decide whether your existing purchases are brought into the vault as shared or private.
• If a member leaves the vault or is removed by the owner, the purchases they shared remain in the vault with their documents and are assigned to the owner; private purchases go with them into a vault of their own.
• If a member deletes their account, their shared purchases remain in the vault; their private purchases are deleted. If the owner deletes their account, the vault passes to the longest-standing member.
• These consequences are shown before joining and must be acknowledged. What you share is your own decision – before joining and afterwards for each purchase.

Members decide among themselves which receipts they share. Kayio does not mediate between members. Requests to delete or redact receipts filed by other members – including after leaving – can be sent to privacy@kayio.app; how they are handled is described in the Privacy Policy.

Free allowances (for example for warranty reminders) and Premium apply to the vault as a whole, not per member.

6. Email forwarding, Gmail add-on and fair use

Kayio provides you with a personal forwarding address. Emails sent to this address are attributed to your account. Forward only order and shipping emails intended for you, and do not pass the address on to third parties.

The Gmail add-on processes only the email you currently have open, and only when you trigger the filing. Google's terms apply to the add-on in addition.

To protect against misuse and to limit the cost of automatic recognition, technical limits apply (for example to the number of recognitions per day). If they are exceeded, individual features are temporarily restricted. Automated or bulk use of the service outside its intended features is not permitted.

7. Your content

Receipts, emails, photos and other content you file in Kayio remain your content. You grant us the simple, non-transferable right to store and process this content (including resizing and converting) in order to provide the service, to transmit it for automatic recognition to the service providers named in the Privacy Policy, and to display it to the members of your family vault. It is not used for any other purpose, in particular not for advertising or for training AI models.

You may only file content you are entitled to use, and no unlawful content. In the event of legal violations or misuse we may remove individual content or block access; we will inform you where permitted.

8. Premium (where offered)

We may offer paid Premium features, for example unlimited warranty reminders (free: five per vault) and the export of warranty documents. Which features Premium includes is stated in the app and in the respective app store.

Premium is purchased exclusively as a subscription through Google Play or the Apple App Store. Price, term and renewal are shown to you there before purchase; currently envisaged are €29 per year or €3.49 per month including VAT, or the price shown in other countries. The subscription renews automatically for the chosen term unless you cancel it before it ends in the subscription settings of the respective store. Purchase, billing, renewal, cancellation and refunds are handled by the store operator under its terms; you also exercise any statutory right of withdrawal there.

Premium applies to your whole family vault. When Premium ends, everything filed remains readable; the free allowances apply again.

9. Availability and development

We strive for high availability but cannot guarantee it; maintenance and faults may temporarily restrict the service. We continue to develop Kayio and may change, add or discontinue features insofar as this is reasonable for you. We announce significant restrictions at least four weeks in advance by email and give you the opportunity to export your documents.

10. Term and termination

Free use is for an indefinite period. You can delete your account at any time in the app settings or via the page kayio.app/en/delete-account; the consequences for the family vault follow from section 5.

We may suspend or terminate your account if you seriously or repeatedly breach these terms, as a rule after a prior warning; in the case of misuse that endangers the service or third parties, also immediately. If we discontinue Kayio, we give at least four weeks' notice by email; current Premium subscriptions are then not renewed, and amounts already paid for the period no longer provided are refunded.

11. Liability

We are liable without limitation for damage resulting from injury to life, body or health, for intent and gross negligence, and under the German Product Liability Act.

In the case of slight negligence we are liable only for the breach of essential contractual obligations – obligations whose fulfilment is a prerequisite for the proper performance of the contract and on whose observance you may regularly rely – and limited to the foreseeable damage typical for the contract.

Otherwise liability is excluded. This applies in particular to disadvantages resulting from an automatically recognised detail being incorrect, a deadline being estimated or a reminder not being delivered, unless we are guilty of intent or gross negligence. Insofar as the use of Kayio is free of charge, the statutory standards of liability for gratuitous services remain unaffected.

12. Privacy

How we process personal data is explained in the Privacy Policy at kayio.app/en/legal/datenschutz. It is not part of these terms but informs you about the processing.

13. Changes to these terms

We may change these terms where there is a valid reason, for example a change in the law or case law, new or changed features, security requirements or a gap in the rules. We notify you of changes by email at least four weeks before they take effect. If you do not object before they take effect, the changed terms are deemed accepted; we point this out specifically in the notification. If you object, either side may end the user relationship at the time the changes would take effect. The main service and the prices of a Premium subscription already concluded do not change by this route.

14. Final provisions

The law of the Federal Republic of Germany applies, excluding the UN Convention on Contracts for the International Sale of Goods. If your habitual residence is in another state, the mandatory consumer protection provisions of that state remain unaffected.

We are neither willing nor obliged to take part in dispute resolution proceedings before a consumer arbitration board (section 36 of the German VSBG).

Should any provision of these terms be invalid, the validity of the remaining provisions remains unaffected.

Questions about these terms: privacy@kayio.app