Privacy statement

What data the Halster app and this website process, how we use it and what rights you have. Adopted on 10 October 2026.

The Halster app

The privacy statement is also available in the app under Profile › About Halster.

What this policy covers

Halster stores what you enter about your horse, what is needed for your account, and data about the app’s use and operation. Halster does not show adverts or sell your data. We use our own system to measure app usage.

Who is responsible

Halster is responsible for the processing of personal data described in this policy. For questions, contact contact@halster.app.

Account and devices

For your account, we process your email address, account identifier, the details supplied by Apple or Google when you sign in, and the name you enter. We also store information about signed-in devices, such as a device identifier, the app version and your access to Halster. This data is needed to identify you, let you sign in and make your data available through your account.

Trial, purchases and free Premium

For your trial, Halster’s server stores the start and end times. When you make a purchase, we process which subscription you bought, the purchase date, the expiry date, whether the subscription renews, any refund or revocation, Apple’s transaction identifiers and the link to your Halster account. Apple also sends us updates about changes to your subscription. If Halster grants you free Premium access, we store the email address it applies to, the reason for the grant (beta group, ambassador, an earlier promise on the website or another reason), a short internal note from the administrator, the end date or the fact that there is no end date, the link to your account and when it was made, and whether and when the grant was withdrawn. Halster also records the grant if you do not yet have an account. We use the data about your trial, purchases and granted free Premium access to determine your access to Halster. We also use the email address for the email about newly granted free Premium access. If you do not yet have an account, that email invites you to create one using that address. Apple handles payment for purchases. Halster does not receive payment details such as your card number or bank account number.

We use your trial’s end time and the confirmed email address of your own account to send you one email 72 hours before the trial ends. It explains when your trial ends and what changes afterwards. If you create an account and confirm your address during the final 72 hours, we send the email afterwards, while your trial is still running. We do not send it if you already have a subscription or a valid Premium grant, or if your trial has ended.

Your horse and what you enter

We store the data you enter and add: horse details, photos, documents, feed charts, feeds ticked off, appointments and amounts entered for appointments, measurements, observations, notes, training sessions and rides. We also store the contacts you enter, including their name, role and phone number. We receive these contacts’ details from you. For the stable’s hay batch, we store details such as the supplier, cut, number of bales and analysis data, including when you enter an ordered batch that has yet to arrive. We store the rounded stable location with your stable data, including online when you are signed in. We use this data for your entries, overviews, plans and the weather for your stable.

Rides and location

If you allow location access and record a ride, Halster stores the precise GPS route, timestamps and ride data, such as duration and distance, on your device. When you save the ride while signed in, this data is also sent to Halster’s server. The rounded stable location is used separately for weather, including the server’s weather checks. You manage location permission in your device settings. Apple Maps supplies the map images and receives information about the map area your device requests.

Where your data is stored

Your data is stored on your device. When you are signed in, data is exchanged with Halster’s server. The storage status shows what has been confirmed online. The app server runs on Railway in Amsterdam; the database, account services and files are hosted by Supabase in Ireland. Encrypted server backups are stored with Cloudflare R2 in the European Union. Without an account, local data may be included in your device’s configured iCloud or Finder backup. This is not synchronisation with a Halster account.

Sign-in and email services

Apple and Google process data when you use their sign-in service. Supabase provides Halster’s account service. Resend sends emails on Halster’s behalf, including sign-in codes and the email about the end of the trial, and processes email addresses, message content, and sending and delivery information for this purpose. Email to contact@halster.app passes through Namecheap’s forwarding service to the personal Gmail mailbox of Halster’s owner. This is a regular Google account, not a Google Workspace account. Only Halster’s owner reads this mailbox. The email services involved process your message and any attachments to receive and handle it.

Weather

The app requests a weather forecast directly from Open-Meteo using the stable location rounded to approximately one kilometre. Open-Meteo also receives your device’s internet address. In addition, Halster’s server checks the weather every hour for each stable with active horses. The server makes one request per grid cell of approximately five kilometres; it does not send the stable’s exact location to Open-Meteo. Only if the advice for a horse could change does the server send a silent notification to the app. According to Open-Meteo’s privacy information, location data from requests and internet addresses may appear in technical logs, which are deleted after 90 days.

Our usage measurement

We measure how the app is used to improve its operation and investigate problems. For example, we store when you open the app and sign in, which screens you open and for how long, what you tap, and the type of action you take, such as ticking off a feed. This may include your account, device, session, horse identifier, language, country and app version. Free-text content and photos are not included in these usage measurements.

Usage before sign-in

Usage measurements from before sign-in are collected locally and may be linked to your account after sign-in. Halster also receives separate counts of starts and failed sign-in attempts without an account identifier. An objection to our usage measurement that has already been processed remains in effect.

Errors and performance

To operate and secure the service, we process technical data about devices, synchronisation, server requests and errors. This may include an identifier derived from an internet address. From Apple’s reports, we count how often the app crashes, hangs or starts slowly, by app version and device model. These counts are not linked to your account in our own storage.

Notifications

Your iPhone schedules reminders itself. We send messages from Halster, such as a notification about signing in on a new device, through Apple’s notification service. For testers, these may also include a message about a new version. Silent notifications following a weather check also pass through Apple. They signal the app in the background when the advice for a horse could change; this does not itself display an alert. For notifications through Apple, we store the notification address Apple assigns to your device. Your device can report whether a notification arrived without sending the message content back. You choose notification preferences in Profile › Notifications. You manage permission to show notifications in your iPhone settings. Turning off visible notifications does not automatically stop the server’s weather checks or all silent notifications.

Who receives data

Halster and the service providers named here process data for the functions described, support, security and administration of the service. Authorised people who administer Halster may access data for these purposes. Your horse data is not displayed to other users as a public profile. A backup or other file you choose to share goes to the recipient you select. When you make a purchase, Halster sends Apple an identifier for your Halster account. Apple stores it with the transaction so that Halster can link the purchase to the correct account. Apple processes your purchase and payment through the App Store and sends Halster the purchase data and subscription updates described above. Resend receives the data needed to send the email about the end of your trial and the email about granted free Premium access.

Contact with Halster

If you email contact@halster.app, we process your email address, subject, message, timestamps and any attachments to handle your enquiry. Your message is handled by email.

Purposes and legal bases

We process your account data and the data you enter to provide your account and the functions you use. This includes online storage, saving a ride with its route, weather for your stable, reminders, necessary account messages and account support. For the trial and purchases, we process the data described above to determine your access and send the email about the end of your trial. The legal basis is the performance of our contract with you.

For security, investigating faults and answering other enquiries, we rely on our legitimate interest in keeping Halster safe and reliable and handling correspondence. For the names, roles and phone numbers of contacts you enter, we rely on your and Halster’s legitimate interest in organising your horse’s care. Only enter details needed for that purpose.

For our own usage measurement, we rely on our legitimate interest in understanding which functions are used and where the app can work better. You can object as described below. We handle requests about your privacy rights to meet our legal data protection obligations. Location permission or permission to display notifications in your device settings is separate from these legal bases for processing.

Processing outside the European Economic Area

The European storage locations do not mean that all processing stays within the European Economic Area. This comprises the European Union countries, Norway, Iceland and Liechtenstein. International service providers may also process or access data outside this area. For such transfers, we use a European Commission decision recognising that the receiving country provides adequate protection, or the European Commission’s approved standard contractual clauses, with additional safeguards where needed. You can request an explanation and a copy of the applicable safeguards at contact@halster.app.

Resend stores email data in the United States. Its published data processing agreement provides for the European standard contractual clauses for these transfers. Railway states that it processes data in the United States and participates in the EU-US Data Privacy Framework. Its published data processing agreement also includes standard contractual clauses. Supabase identifies Singapore and the United States for processing and support outside the European Economic Area, with standard contractual clauses as a safeguard. Cloudflare lists the United States, the United Kingdom, Singapore, Australia, Japan, Canada, the United Arab Emirates, South Korea, Mexico, Malaysia, India and Switzerland as possible support locations. Cloudflare states that it uses the EU-US Data Privacy Framework for transfers to the United States covered by that framework, and standard contractual clauses for transfers not covered by an adequacy decision. When you sign in with Apple or receive push notifications through Apple, data may be processed or accessed worldwide, including in the United States. Apple states that it uses standard contractual clauses for international transfers. Google’s general privacy policy applies to Google sign-in and contact emails in Gmail. Google may process this data worldwide, including outside the European Economic Area and in the United States. Google states that it uses adequacy decisions, the EU-US Data Privacy Framework for transfers to Google LLC and US subsidiaries covered by its certification, and standard contractual clauses where needed if no adequacy decision applies. Namecheap identifies processing in the United States; its published data processing agreement provides for standard contractual clauses for transfers that require them. Open-Meteo’s privacy information does not specify transfer destinations or the corresponding safeguards. The countries named here are not a complete list of all possible processing and access locations for these services. Halster’s own server backups are encrypted before transfer and stored within the European Union.

Retention and deleting individual entries

Account and horse data is retained while your account exists, unless you delete data earlier. When individual entries are deleted, their content may remain in the database for up to 180 days; the app then receives only a deletion marker. An individually deleted photo or document file is removed from active file storage after 30 days. Deletion of an entire account follows the separate process below.

What happens when you delete your account

Request account deletion in Profile › Delete account. During the following 30 days, we do not yet erase your data and you can cancel the request. We then carry out the deletion. Completion may be postponed while an export is still being processed or remains available for you on the server. When deletion is carried out, we remove your account and horse data from active storage, together with linked usage data. Technical audit entries and file metadata without the original content are retained without a fixed end date. An email address blocked because mail was undeliverable or reported as unwanted is retained to prevent further mail to that address. Contact emails are subject to the separate retention periods below.

Backups and other devices

After account deletion has been carried out, data may remain in server backups for up to 30 days. A backup file you have saved yourself is not deleted by this process. Local data on other devices is not automatically removed everywhere either. Delete these copies yourself if you do not want to keep them.

Retention periods for usage, technical data and messages

We retain your trial’s start and end times and the purchase data described above, including its link to your account, while your account exists. For the account deletion process and retention periods, see the sections “What happens when you delete your account” and “Backups and other devices”. When account deletion is carried out, we remove your email address and the internal note from the data about granted free Premium access, remove the link to your account and withdraw the grant. We retain account-linked usage measurements and app usage activity for 180 days. After that, only counts with no link to a person remain. This period concerns app usage, not the training sessions and rides you save. We retain technical service measurements for 90 days. In our own email sending logs, we delete outgoing email content after 30 days; sending and delivery information is retained for 1 year. These email retention periods also apply to the email about the end of your trial and the email about granted free Premium access. Sending information for completed push messages is cleared after 30 days. We retain handled or dismissed notifications for a further 90 days.

Contact emails and data held by email services

We retain contact emails for no longer than 12 months after your enquiry has been resolved, so we can understand a follow-up enquiry. We then delete the messages and attachments from the mailboxes Halster uses to handle correspondence. If specific documents are still needed for an ongoing dispute or a particular legal obligation, we retain only those documents for longer. We record why this is necessary and when they can be deleted.

According to Resend’s published information, it retains email data and related logs for 30 days. Resend’s backups have a retention period of 7 days. These periods are separate from the contact emails retained by Halster itself.

Other service providers’ technical logs

Service providers may retain technical data about connections, delivery and errors to operate and secure their services. Under its general privacy policy, Railway retains device and IP data for as long as it is needed to keep its systems working properly; legal obligations or disputes may require longer retention. Supabase retains logs and technical measurements for operational and security purposes, but does not state a specific deletion period for them. Its data processing agreement requires data covered by that agreement to be deleted after a retention period of 30 days following the agreement’s expiry. This concerns the agreement with Halster, not deletion of your Halster account. Under its general privacy policy, Cloudflare determines retention by the purpose, nature and sensitivity of the data and legal obligations. Cloudflare then deletes or destroys the data, or uses security measures to prevent further use if deletion is technically impossible. Under its general policy, Apple retains personal data for as long as it is needed for the stated purposes or a legal obligation. Under its general retention policy, Google determines retention by data type and purpose; security, preventing abuse and legal obligations may require longer retention. The following also applies to contact emails in Gmail. Deleted messages remain in the bin for 30 days unless the owner permanently deletes them from there sooner. After those 30 days, Gmail permanently deletes them from the mailbox. Google’s general deletion process usually takes about two months, often including a recovery period of up to a month. Data may remain in encrypted backups for up to six months. Google notes possible delays; these general periods do not guarantee a final deletion date for an individual Gmail message. Namecheap’s data processing agreement uses the time needed to provide the service or required by law as its criterion. These criteria do not set a fixed retention period for every technical log. The sources consulted do not confirm a separate deletion period for all connection, delivery and error logs held by Railway, Supabase, Cloudflare R2, Apple for sign-in and push notifications, Google for sign-in and Gmail, and Namecheap for email forwarding. Resend’s retention periods are stated above under Contact emails and data held by email services; the period for Open-Meteo’s weather logs is stated under Weather.

Your rights

You can request access to, correction, deletion, restriction of processing or transfer of your personal data, and object to processing. Email contact@halster.app to do so. You can also view your available app data and create a backup file in Profile. You can complain to the data protection authority in your country. In the Netherlands, this is the Autoriteit Persoonsgegevens.

Objecting to usage measurement

If you do not want us to measure your usage, email contact@halster.app. We turn off account-linked usage measurement and delete the associated usage data. Earlier counts with no link to a person remain. Data needed for your account, horse data, technical operation and security is still processed.

Age

Halster is for people aged 16 and over.

Requests in the test version

Other testers can read requests, descriptions and additions you post in the test version without seeing your account name as the author. Halster does link your submissions and votes to your account to operate Requests and assess feedback. Your own requests, additions and votes are deleted when your account is deleted.

For posting requests, additions and votes, the legal basis is the performance of our contract with you. For assessing this feedback, we rely on our legitimate interest in understanding problems and improving Halster.

Changes and contact

The date at the top identifies this adopted version of the privacy policy. If the processing described here changes, we update the policy and give the adopted text a new version date. Send questions to contact@halster.app.

This website

Who is responsible

The maker of Halster, reachable at contact@halster.app, is responsible for the processing of your data on halster.app and in the Halster app.

Company name, registered office and registration number will appear here as soon as the registration is complete.

What the site does not do

No ads, no trackers and no third-party analytics. The site loads nothing from third parties. The site sets a cookie only when you ask for it: your language choice on these pages (only “nl”, “en” or “de”), and “don’t count” when you choose on halster.app/niet-meetellen not to count this device (only “1”, as a cookie and in your browser’s storage; meant for the Halster team, so their own visits stay out of the figures). Both expire after a year.

Language choice

Without a saved language choice, the site may redirect you from its Dutch pages (home, help, iPhone, Android, privacy and terms) to the English or German version based on your browser language. This does not set a cookie. When you use the language button, your choice is saved for one year in the “taal” cookie (“nl”, “en” or “de”). Any of these saved choices, including Dutch, prevents this automatic redirect.

What we count

To measure how the website is used, we count each day: how often a page was viewed, how often the App Store button or the test button was pressed, how often a waitlist sign-up was started, requested, confirmed or withdrawn, how often the questions after sign-up confirmation were answered, and how often a tool or PDF from the guide was used. If you arrive through a channel’s own address, such as halster.app/via/flyer, we also count those steps per channel; the channel name travels in the address of the pages, not in a cookie. These are plain counts without IP address, without device data and without any link to a person. They are stored on a server in the European Union.

The waitlist

If you leave your e-mail address for Halster on Android or for a message once the app is in the App Store, we store that address with the platform you signed up for, the moment of signing up and, if you arrived through a channel address, the name of that channel. We first send one confirmation e-mail; if you do not confirm, we delete the address after seven days. If you do confirm, we use the address with your consent solely to let you know there is news about Halster on that platform. No newsletter, no other messages. Signing up creates no app account and starts no subscription or trial.

If you sign up for the test, we store that with your address too. After you confirm, we send you an invitation to the test by email within a few days. If we invite you through TestFlight, Apple’s app for test versions, Apple receives your email address for this and sends the invitation.

Every e-mail has an unsubscribe link with which you can withdraw your consent. Unsubscribing removes your address from the waitlist. The addresses are kept in a database in the European Union (Ireland). We use Resend to send the e-mails; that service processes your address and the content of the e-mail in order to deliver it.

Questions after sign-up confirmation

After you confirm your sign-up, we ask two short questions (what you would use Halster for first, and what you think of the planned price) and one open question. Answering is voluntary. We keep your answers with your sign-up, so that we can look at answers from confirmed sign-ups separately. We use them only to decide what to build first and whether the price is right; they are not passed on to anyone. If you unsubscribe, or your sign-up lapses after seven days without confirmation, your answers are deleted with it.

Server log

The hosting provider briefly keeps technical log lines to resolve outages. We do not keep any personal data from them ourselves.

Your rights and contact

You may ask what we hold about you, have it corrected or have it erased. One e-mail to contact@halster.app is enough; you will hear from us within a month. If you disagree with how we handle your data, you can lodge a complaint with the data protection authority in your country.