Terms of use

Version of 8 September 2026

1. What this document is

An agreement between you and individual entrepreneur Maksim Sergeyevich Kuznetsov (TIN 773391216156, state registration number 326508100402717) — “we” below — about the use of the Tessera mobile app and the website tessera-app.ru.

By installing and using the app you accept these terms. If you do not agree, do not use it; deleting the app ends the agreement on your side.

The Russian text of these terms, published at tessera-app.ru/legal/terms, is the governing version. This English text is provided for convenience; if the two ever differ, the Russian one applies.

2. What Tessera is

An app for keeping a personal diary: ratings of your own state, habit marks, sleep times, time by category, notes, photos and voice notes. From those entries the app builds weekly, monthly and yearly reports.

We grant you the right to use the app for its purpose, on any number of your devices, without a time limit. The rights to the app itself, its source code, design, texts and icons remain ours.

Tessera has two parts, and the difference between them matters, because your rights and our duties follow from it:

• The app on your device. The diary, the entries, the reports and the insights. It works without the internet and without our server. The right to use it has no time limit and we cannot take it away.
• The services that need our server. The cloud copy of the diary and support. They exist for as long as the service runs; section 5 says what happens if it stops.

3. What you may and may not do

You may: keep a diary, export a copy of it, move that copy to another device, and use the app for as long as you like.

You may not:

• reverse-engineer, decompile or modify the app, except where the law expressly allows it;
• resell access to the app or to its server-side features;
• deliberately overload or break our server, or use the cloud storage for anything other than a copy of your own diary.

For a breach we may refuse access to the server-side features. The diary on your device remains yours and keeps working.

4. Who may use the app

The app is not meant for children under 13 and is not designed for them, either in content or in appearance. We collect no information about age and have no way to verify it: there is no sign-up and no account.

5. If the server-side services stop or the project closes

We write this out in advance and in detail, because a diary is something people keep for years. Anyone who puts their days into an app is entitled to know what becomes of them if all this ends one day — rather than finding out on the day it does.

What never stops. The app on your device and everything written in it. The diary lives in your phone’s memory, works without the internet and asks us for no permission. We cannot switch it off remotely, erase your entries, or take away features that work on the device.

What may stop. The services that need our server: the cloud copy of the diary and support. We may discontinue them — in whole or in part — on the conditions below.

At least 90 days’ notice. We will announce it in the app and on this page. Ninety days is enough time to download the cloud copy and move the diary somewhere else without hurrying.

A final update removes any dependence on the server. Together with the announcement we release an update in which every feature of the app works without our server — for everyone, including people who install the app later. Shutting our services down must not leave you without what the app already gave you.

Exporting the diary. Until the shutdown the cloud copy stays available for download for the whole notice period. Independently of that, exporting the diary to a file works in the app at all times and needs no server: Settings → Export data.

A cloud copy left untouched for a long time. Separately and in advance: if the app has not reached the server for its copy in over a year, we may delete it. We cannot keep files nobody will come back for indefinitely — and saying so beforehand is fairer than presenting you with the fact one day. The diary on your device is unaffected: a copy is a copy.

Transfer of the project. We may transfer our rights and duties under this agreement to another person if the project passes to them in full. We will give at least 30 days’ notice in the app and on the site. Your rights are not reduced, and the new owner is bound by the same terms. If you would rather not deal with the new owner, you may ask us to delete your data, as described in the privacy policy.

Things outside our control. We are not liable for failures caused by what we cannot influence: a hosting provider going down, restrictions imposed by app stores, changes in the law, network outages, natural disasters. If such a circumstance lasts long enough that the server-side services have to end, the procedure in this section applies, notice included.

Closing the project altogether. The same, in the same order: 90 days’ notice and a final update that needs no server. The app stays with you and keeps working — it will stop receiving updates, but the diary depends neither on us nor on the network.

Nothing in this section takes away rights the law gives you as a consumer. Where our rules turn out to be worse than the law, the law applies.

6. Your entries belong to you

Everything you have written is yours. We make no claim to the content of the diary, use it for nothing and, with one exception, have no access to it: the diary is stored on your device.

The exception is the cloud copy, if you switched it on. It is encrypted on your phone before sending, and we cannot read it: we do not have the key. Details are in the privacy policy.

Keeping your entries safe is on you: make copies. The app can do both a file and the cloud — but the decision to make a copy stays yours.

7. The app does not replace a doctor

Tessera is a diary, not a medical device. It makes no diagnosis, prescribes no treatment and is not a means of preventing or treating any condition.

Reports and insights show links between your own entries — that is an observation, not a conclusion. Do not make decisions about your health on their basis. If you feel unwell, see a specialist.

8. Liability and availability

We do our best to keep the app working, but cannot promise that it will always work without errors or interruptions. The server side may be unavailable because of maintenance or a failure at the hosting provider; the diary keeps working meanwhile — it does not depend on the network.

We are not liable for a loss of entries caused by damage to or loss of your device, by deleting the app, or by losing the recovery code of the cloud copy.

Nothing in this section limits your rights as a consumer under the law.

9. Changes to the terms

We may change these terms. A new version is published on this page with the date.

If something substantial changes — the way the services work, the periods in section 5 — we will say so in the app at least 30 days before the new version takes effect. Edits that change no substance (typos, clarifications, wording) take effect on publication.

10. Law and disputes

The law of the Russian Federation applies.

If something went wrong, write to us first: most questions are settled by correspondence within a day. We answer a claim within thirty days.

If an agreement cannot be reached, the dispute is settled in court. As a consumer you are entitled to apply to a court at your place of residence or stay — that right is given to you by law and we do not limit it.