136 questions and answers about JSEM TU!

JSEM TU! is a Czech community app for taking part in regular activities together. It brings together group organisation, meeting times and locations, attendance check-ins and a record of how regularly people take part. Individual activity types can add their own tools, such as the Cold-Water Swimming Diary.

No. JSEM TU! provides a shared foundation for different kinds of community activity. Cold-water swimming is the first specialism to be developed in detail, but the same community features are also intended for running, hiking, cycling, swimming, fitness, team sports, outdoor activities, volunteering and more.

JSEM TU! means ‘I’m here!’ in Czech. The name comes from the app’s main action: participants confirm that they have actually arrived at an activity, at the right place and time. The exclamation mark is part of the JSEM TU! brand name.

JSEM TU! is for people aged 9 and over. Users aged 9–15 inclusive need approval from a parent or legal guardian before using it. From their 16th birthday, they accept the terms themselves. The app is designed for people who regularly meet for sport or other shared activities, and for the organisers of those groups.

It gives a group one place to manage its schedule, meeting location, membership and confirmed attendance. The Cold-Water Swimming Diary adds personal records, statistics and ways to share results.

Otakar Zemek is the project’s creator and operator. The app draws on his practical experience of many years of cold-water swimming and organising the Otužilci Frýdek-Místek community.

No. The community features and the Cold-Water Swimming Diary, including charts, sharing and export, are already working in public open testing. The app remains in active development, with further changes checked in the DEV environment before release.

Google Play release v142 / B267alo was published on 23 September 2026 at 11:31. It is available in open testing in Czechia and Slovakia for users aged 9 and over, with parental approval required until their 16th birthday. This release adds a summary of errors when creating or editing activities, clearer navigation, smoother logo loading and more readable diary sharing. The public feature descriptions refer to this release.

The shared core will be the same: accounts, communities, activities and attendance. However, each activity type may have its own diary, statistics and fields suited to that activity, so the cold-water swimming, running and fitness versions need not be identical.

It describes the latest approved Google Play release as of the date shown. The ‘In public testing’ label identifies features already available in that release.

JSEM TU! costs CZK 0. It is free for both participants and organisers, and the current version does not require a paid subscription.

No. The current version does not display advertising banners or video ads.

No. JSEM TU! has no paid Premium tier and no purchases for individual features.

Yes. It is available in Google Play open testing in Czechia and Slovakia for users aged 9 and over, with parental approval required until their 16th birthday. There is no need to join a tester list; parental approval for a child’s account is a separate step. The app’s listing is at play.google.com/store/apps/details?id=info.jsemtu.app.

Yes. You can use the BETA test version in a modern web browser at beta.jsemtu.info without installing anything. You need to sign in to use personal features.

Yes. Open beta.jsemtu.info in Safari on your iPhone and use Share → Add to Home Screen to add JSEM TU! as a web app. Share is the square icon with an upward arrow; depending on your Safari layout, it is on the toolbar or under More (three dots). The next answer gives detailed instructions. A separate native iOS app has not yet been publicly released in the App Store.

Yes. On an iPhone: 1. Open beta.jsemtu.info in Safari. 2. Tap Share (the square with an upward arrow). If it is not on the toolbar, first open More (three dots), then Share. 3. Scroll down the list of sharing options and select Add to Home Screen. If the option is missing, add it through Edit Actions at the bottom. 4. If you see an Open as Web App switch, turn it on and tap Add. You can then launch JSEM TU! using the home-screen icon. On Android, you can add the web version from a supported browser’s menu; the wording may vary. The iPhone instructions were checked against Apple’s guide on 23 September 2026.

Yes. JSEM TU! is a Czech project, and its current user interface is in Czech.

These sport and health integrations are not part of the verified public release. Diary entries are entered in the app; attendance at cold-water swimming activities can be added automatically.

No. In the current Cold-Water Swimming Diary, temperatures and other values are entered manually. Automatic connections to Bluetooth thermometers or watches are not part of this version.

Yes. Your account connects you to your activities, memberships, attendance records, rankings and personal settings.

Yes. The app supports registration with an email address and password, with a code used to verify the email address.

Yes. JSEM TU! supports Google sign-in; the exact steps may differ between the web and Android versions.

Not in the current version. Facebook sign-in has been removed from both the available Google Play release and the web BETA. Use an email address and password, or Google. If you previously used only Facebook, contact support for help accessing your existing account.

You can request a password reset. A verification code will be sent to your email address. Once you confirm it, you can set a new password.

Yes. Your profile includes a process for changing your email address and verifying the new one.

Yes. If you are signed in using email and password, you can manage your password in your profile. You can also use the password-reset process.

Your profile uses your first name, surname and, optionally, a nickname. Your display name is used wherever members or their attendance need to be identified within the community.

Yes. Sign in with the same account and allow the diary to load from the server while connected to the internet. Changes may not appear immediately in a list already open on another device. A collage in progress, its photographs and local filters do not sync between devices.

Yes. Your profile first lets you review the consequences of deleting your account, then delete it. If you are an activity’s lead administrator, you may first need to transfer or delete that activity.

JSEM TU! is available from age 9. Users aged 9–15 inclusive need approval from a parent or legal guardian before using it. From their 16th birthday, they accept the terms themselves. Children under 9 cannot complete registration. The same rule applies to the available Google Play release and the web BETA.

During registration, enter the child’s correct date of birth and the parent’s name and email address. The parent opens the link in the email, checks the details, reads the documents and approves or rejects the request. The child’s account cannot be used normally until approval is granted. Once approved, the child completes registration by following the instructions sent to them.

Yes. The request goes to a separate email address belonging to the parent or legal guardian. Simply entering that address does not mean consent has been given.

No. Google verifies access to the account. The user’s correct age and any required parental approval are also checked when completing a profile after Google sign-in. Children can use an email address and password; a Google account is not required.

Yes. A request can be rejected, and consent already given can later be withdrawn using the consent-management link. Without valid approval, the child’s account cannot be used normally. If the approval link expires, a new one must be requested.

No. The app’s age limit determines who can create an account. Parental approval for an account does not replace assessing whether a particular activity is suitable or supervising a child. The diary’s optional Cold-Water Swimmers’ Competition is available from age 15 to users with a completed profile.

The app offers running, walking and hiking, cycling, swimming, cold-water swimming, exercise and fitness, team sports, outdoor activities, volunteering and a general ‘other activity’ option.

In the ‘Vybrat’ (Choose) section, you can browse the public directory and filter by distance and activity type. Results can be sorted by name or proximity.

Yes. If you allow location access, the directory can use your distance from activities to display or sort them by proximity.

Yes. The directory has activity-type filters, such as cold-water swimming, running, hiking and fitness.

It is a permanent identifier that lets you find a particular activity without browsing the whole directory. The code does not change after the activity is created.

Yes. An administrator can choose public or hidden visibility. A hidden activity is not normally shown in the directory, but members still see it among their activities, and it can be found using its exact code.

It depends on that activity’s settings and rules. The app supports both direct joining and membership requests that an administrator must approve.

Yes. The approval process forwards requests to administrators and lets them accept or reject them. The system also includes decision links sent by email.

Yes. You can withdraw a pending request before an administrator makes a decision.

Yes. An ordinary member can leave an activity. Administrators or owners may first need to take steps to ensure someone remains responsible for managing it.

Yes. The ‘Založit’ (Create) section guides you through creating an activity. You then become its lead administrator.

Its name, type, visibility, location, coordinates, permitted check-in radius, season, weekly schedule and joining rules. An activity can also have its own logo.

Yes. The form includes a map picker and supports both coordinates and the device’s current location.

Yes. The administrator sets a verification radius in metres. The default is 100 metres, but an activity may use another valid setting.

Yes. The administrator sets the days, times and check-in windows.

Yes. You can switch the schedule to 24/7 mode, making the activity available all day and night, every day.

Yes. An activity can have a season start and end date, which are used to calculate attendance and rankings.

Yes. The lead administrator can give another active member an administrator role. The app distinguishes between ordinary administrators and the activity’s lead owner.

Yes. The app has a controlled ownership-transfer process involving a request and confirmation by the recipient, to prevent accidental transfers.

Yes. An authorised administrator can manage and remove members. The rules protect the lead owner and higher-level roles against unauthorised changes.

Open your activity and use the JSEM TU! action. The app checks your membership, the check-in window and, depending on the settings, your distance from the activity’s location.

Not always. For a scheduled activity, the administrator sets how many minutes before and after the start check-in is available. In 24/7 mode, it is available throughout the day.

If the activity uses location checks, yes. The app compares your device’s location with the activity’s location and the permitted radius.

The app shows the current status and can refresh your location, but it cannot guarantee perfect accuracy. GPS is affected by your phone, surroundings, power-saving mode, signal quality and connection.

Yes. A successful check-in creates an attendance record linked to you and the activity. It is used for attendance history, totals and rankings.

Yes. The activity card and rankings show an overview of your regular attendance and the number of sessions counted for the relevant period.

Members can view their activity’s rankings and attendance totals. Stars for regular attendance depend on the activity’s settings and an eligible season; they are not automatically enabled for every activity.

Yes. The default period follows the calendar year or the activity’s season. You can also select a custom range of up to 366 days.

Yes. Members can set reminders for their activities and choose the days and advance notice to match the schedule. Notifications depend on permissions granted on the phone or in the browser.

No. It serves community, information and organisational purposes. The app is not a workplace attendance, safety, rescue or emergency system, and its records should not be the sole evidence for decisions with serious consequences.

Yes. The diary is available in both the web BETA and Google Play open testing. The app is for users aged 9 and over and requires parental approval until their 16th birthday. The diary’s optional competition has separate age requirements.

Cold showers, cold baths in a bath or tub, and outdoor swimming. Statistics and charts can show these three types together or separately.

The date, time, type of cold-water exposure, location, water temperature, air temperature, time in the water, how you felt before and after, and a note. For outdoor swimming, you can also enter the distance swum.

An entry needs a date and a type of cold-water exposure. Other values are optional, so you can save a brief entry. However, charts and individual competition categories may require the relevant measurements.

Yes. The controls support decimal water temperatures and check that values are within a reasonable range for cold-water exposure.

A numerical scale from 1 to 5. These ratings remain numbers in exports so that you can calculate with them and use them in filters.

Yes. Selecting ‘Plavání venku’ (Outdoor swimming) shows an optional field for whole metres. Distance is neither shown nor stored for showers or cold baths.

Yes. It suggests confirmed locations you have previously used in your own diary, keeping them separate where the context requires it.

Yes. It shows changes relative to the previous entry of the same type, so it does not make misleading comparisons between a shower and an outdoor swim.

Yes. The diary allows multiple entries of the same type on one day, distinguishing them by time and a separate identifier.

Yes. The BETA version includes both basic and detailed statistics based on your personal records.

A week, month, year or custom date range. You can also select one, two or all three types of cold-water exposure.

Total time spent in cold water, the number of entries and active days, average session time and a breakdown by type of cold-water exposure.

For each selected type, they show the lowest, average and highest water temperature, and the shortest, average and longest session time.

As well as time and temperature, they show the shortest, average and longest distance swum and the total number of metres, provided distances have been entered in the records.

No. Calculations use only entries in which the relevant value has actually been entered. Missing times or temperatures therefore do not falsely lower the average.

Yes. Time, temperature and distance show their coverage: how many of the total entries contain that value.

Yes. Interactive charts appear on the ‘Statistiky’ (Statistics) tab below the summary results. They show water temperature and session duration over time, with filters for date range and activity type, and appear once there are at least five complete entries.

Yes. You can adjust the display of data points and follow changes over time without exporting your data to another tool.

No. They display the data you enter and how it changes over time. They do not provide a diagnosis, prescribe a safe amount of cold exposure or assess medical fitness.

Yes. The BETA version’s ‘Sdílení’ (Sharing) tool creates summary collages from selected statistics, charts and up to three of your own photographs.

Currently, it offers a vertical 9:16 Stories format. It is designed for social media stories and lets you move, zoom and crop a photograph before finishing.

Yes. A collage can use a single photograph as a full background, or a layout with one to three photographs alongside metrics or a chart. You can move, zoom in or out, centre and crop photographs.

Yes. You can save the finished PNG image to your device or pass it to the system share dialog.

Yes. The ‘Export’ tab in the diary’s bottom navigation lets you create an Excel XLS spreadsheet.

Excel XLS, semicolon-separated CSV with a UTF-8 BOM for Czech Excel, TSV and JSON.

Yes. You can select all entries, including technical fields, in one step, or create a more focused custom export.

Yes. Choose a week, month, year, all time or a custom date range, and any combination of showers, cold baths and outdoor swimming.

Yes. You can include or leave out basic details, measurements, feelings, notes and technical fields such as the ID, revision and sync status.

Optionally, yes. The XLS file has a ‘Záznamy’ (Records) sheet and can add a ‘Souhrn’ (Summary) sheet with totals, active days, times, temperatures and distances where relevant. You can preview the complete result before saving.

No. The whole app, including the diary, requires an internet connection. A local cache is not an offline mode.

No. Accounts, activities, attendance check-ins and the personal diary are used online. If the connection is lost, the app shows that it is offline.

The current app does not offer normal offline entry creation. If your internet connection drops, wait until it returns and check that your unfinished entry has actually been saved.

Resending the same change uses the same entry identifier. After a connection failure, first check whether it was saved; creating a separate new entry may result in a duplicate.

Entries sync with the server and track their revisions. A diary already open on another device may not show a change immediately; refresh its contents while online. Before uninstalling the app or clearing its data, check that syncing has finished.

No. The current diary also requires an internet connection to edit or delete entries. Once your connection returns, check that the requested change has been completed.

No. Both the preview and the finished XLS, CSV, TSV or JSON file are created locally from diary data already loaded by the app. The export itself is not sent to Firebase to create the file.

Yes, in the practical sense of data portability: you can view them and, in BETA, export them in standard spreadsheet and machine-readable formats. The app’s privacy policy sets out the legal terms for processing personal data.

Yes. JSON includes metadata, selected fields, individual records and an optional summary, making it suitable for automation or transfer to another system.

Yes. The preview includes every selected entry, not just the first few rows. XLS is shown as a spreadsheet with separate ‘Záznamy’ (Records) and ‘Souhrn’ (Summary) sheets.

Primarily to find nearby activities, select a location on a map and verify that a member is within the activity’s permitted radius when checking in.

The app is not designed as a continuous tracking service. It uses location for specific features, such as the current distance to an activity or an on-site check-in. The privacy policy explains the precise technical processing and any storage of derived data.

Details needed for your account and sign-in, your profile name or nickname, activity memberships, attendance, settings and, depending on the feature used, location or distance information.

The privacy policy lists services provided mainly by Google, Vercel and Resend for infrastructure, sign-in, hosting and email codes. The specific list may change as the app develops.

Yes. They are directly accessible in the ‘Více’ (More) section and publicly available without relying on this FAQ page.

No. It does not diagnose conditions, assess medical fitness or determine a safe duration or temperature for cold-water exposure. Health decisions are the user’s responsibility, with advice from a qualified healthcare professional where appropriate.

No. The diary and statistics are organisational and personal tools. They cannot assess currents, ice, weather, your health or other immediate hazards.

He brings around 17 years of personal cold-water swimming experience and many years of organising people and regular community gatherings. This is practical experience as the founder, not a claim to medical qualifications.

No. Availability depends on the internet connection, server status, phone permissions, GPS and the activity’s settings. The app therefore does not promise perfect accuracy or uninterrupted availability.

The ‘Kontakt’ (Contact) option in ‘Více’ (More) is for questions, ideas and problem reports. Development is active, and feedback from testers is part of the process.

Yes. You can choose a teal, original blue or dark blue theme. This changes the colours throughout the app, without changing its features or your data.

Yes. Its interface is designed for mobile use first, while the web version also adapts to tablets and computers.

On the ‘Moje’ (My activities) tab. The home page also highlights the most relevant activity at that moment and whether check-in is available.

Yes. ‘Více’ (More) has a dedicated ‘Návody’ (Guides) section explaining how to get started and use the main features.

Yes. ‘O aplikaci’ (About the app) shows the version and build time. Installations from Google Play update through Google Play; standalone test APKs from the website have their own update process. The web BETA changes when the website is deployed. These channels do not necessarily contain the same release.

Information can quickly get buried in chat messages, which do not reliably separate schedules, membership, locations and confirmed attendance. JSEM TU! keeps these details organised under each activity, so every member sees the same current information.

Members do not have to edit a shared document or find the right row. They check in with one action, and the app applies the rules for time, location, membership and rankings automatically.

It makes the schedule visible, provides reminders, records attendance and shows both personal and group summaries. It is not just about competition: you can follow your own consistency and return to an activity.

It provides one place for activity settings, members, roles, requests, attendance rules and attendance summaries. It reduces manual copying and the need to explain the same basic details repeatedly.

You can find a suitable activity, check its location and schedule, request to join and, once accepted, access the same information as everyone else. For cold-water swimming, the diary helps you record your own experience without paper or scattered notes.

No. Other apps focus on cold water, including Slovakia’s Cold Water Therapy and Germany’s Eisbaden. JSEM TU! stands out through its Czech origins, free access, connection to a real community and detailed Cold-Water Swimming Diary.

In our research on 4 September 2026, we did not find another Czech mobile app with this specific focus. That does not prove none exists or that the situation has not changed. We therefore do not present JSEM TU! as definitively the only working Czech app.

No. It is associated with LKLK s.r.o., a Slovak company based in Bratislava. It may be available to Czech users in app stores, but its country of origin is not Czechia.

Only partly. Android version 3.9 installed and opened, but a new user could not complete standard email registration: the app repeatedly crashed at the required country-selection step because its connection to an external country list was not working.

That would be too strong a claim. We tested a failing email-registration flow on Android. Google sign-in reached account selection, but we did not complete it because we did not want to send personal data to a competitor. An existing account or another platform may therefore work differently.

In earlier research, its website and app-store listings were available, although some descriptions of pricing and integrations differed. This was not a new test conducted on this page’s update date; check the provider’s current offering directly.

Earlier research found advertised features including a timer, temperature, location and weather records, statistics, streaks, community features, clubs and events, and connections to some watches. Check the official Eisbaden website for the current range of services.

Earlier research found monthly and annual Premium options in its App Store listing. We are not reconfirming today’s price here; check the store directly. The verified current version of JSEM TU! requires neither a subscription nor a paid feature tier.

Because people may want different platforms, watch integrations or ways of measuring their activity. What we can fairly describe is where JSEM TU! is strong: a Czech community, organisation of real activities, a detailed diary in public testing, export of your own data and free use.

In one free Czech app, it combines the organisation of real activities, attendance check-ins and a personal Cold-Water Swimming Diary with charts, statistics, collages and export. It is available from age 9, with parental approval required until the user’s 16th birthday.