Privacy policy
Updated 20 October 2026. Operated by Ryan Erkal. Contact ryanerkal1@gmail.com.
Who this policy covers
This policy covers the Logbook website and app. Ryan Erkal is the controller of the personal data described here. You can use the support contact above for privacy requests.
Information we use
We store your account name, email, authentication records, app settings, and the training, nutrition, bodyweight, goals and Coach content you choose to enter. This can include health information. Backed-up check-in photos are stored with their details and a summary of that day’s logs. Public accounts have private equipment and food catalogs. Existing household members can share their catalog entries. Personal activity logs remain separate.
Website visits
Our hosting provider processes technical request data such as your IP address, browser details, requested URL and access time to deliver and secure this website. The website uses Vercel Web Analytics and Speed Insights to count page views and measure page speed. They record the page address, referrer, browser, device type and country. They do not set cookies. Vercel counts visitors with a temporary identifier that resets each day. The public landing page does not require an account, load advertising trackers, or send your training records to an AI provider. Links to external services are covered by their own policies when you follow them.
Waitlist
If you join the waitlist on our website, we store your email address, the form you used and the time you joined. If you join from a creator's link or page, we also store that creator's code and the time you added it. We use your address to send you one email when Logbook is available on the App Store. If you create a Logbook account with the same email address, we add the saved creator code to your account (see Creator referrals and affiliate payouts below) and record that the address has an account. We do not use the list for other marketing, and we do not share or sell it. Creators do not see your email address. Convex stores the list, and we will send the launch email with Resend. We delete the list 90 days after the launch email is sent. To leave the list earlier, contact support and we will remove your address. Your browser also remembers that you joined, so the website does not ask again. It does not store the creator code. Joining is based on your consent, and you can withdraw it at any time.
Emails from Logbook
Logbook emails are optional. Useful Logbook emails cover setup help, your first-week recap, weekly summaries and an occasional note after a quiet week. They can include activity counts, workout and cardio names, and dates you logged. Logbook offers by email cover membership and pricing offers. Both stay off until you turn them on in the app or on the website, and each is separate from notifications. Joining the website waitlist does not turn them on.
We store your choices, when you made them and the wording you agreed to. We also keep a record of each email we send and whether it was delivered, bounced or marked as spam. We do not use tracking pixels to see whether you open an email. Resend sends these emails for us and processes your email address and the email content.
Each email has an unsubscribe link, and you can change your choices in Settings at any time. If an address has a permanent delivery failure or you mark an email as spam, we stop sending to it. We retain a fingerprint of the blocked address after account deletion to prevent unwanted email if a new account uses it. Support can review and remove this block; this does not subscribe you again. These emails rely on your consent, which you can withdraw at any time. The data export includes your choices and send records. When you delete your account, we stop these emails and delete your choices and send records.
Why we use it
We process account and purchase information to perform our agreement with you: provide your account, sync your records, manage access and support you. We rely on your consent, including explicit consent for health information, to process the health data you choose to provide. We rely on our legitimate interests in protecting and maintaining the service for necessary security and diagnostic records. We retain records required by law to meet legal obligations. You can withdraw health-data consent by deleting your account in Settings, or contact support to request withdrawal. Stop entering health information if you do not consent.
Apple Health
Apple Health connection is optional. With your permission, the iPhone app reads steps and sleep, plus any optional distance, active energy and bodyweight data you select. We store the latest 30 days of daily summaries in Convex for your account. Raw samples are processed on the device. You can stop sync and remove imported summaries in Settings without changing the originals in Apple Health or your manual logs. Imported summaries never go to advertising or analytics services. They go to Coach only if you turn on Share with Coach in Settings › Apple Health, which asks for your separate consent. Coach then sends your daily steps, sleep, naps, distance and active energy with your messages through OpenRouter to the AI provider. You can turn this off at any time; it stops new requests and cannot recall data already sent.
Cycle tracking
Cycle tracking is optional and stays off until you turn it on in the iPhone app. When it is on, we store the periods, spotting, symptoms, moods, energy and notes you log, your cycle settings, and the cycles and predictions calculated from them in Convex for your account. If you connect Apple Health in Cycle settings, the app reads your period, spotting and symptom data from Apple Health and stores it with your logs. It also saves the periods, spotting and symptoms you log to Apple Health. You can turn either direction off in Cycle settings.
We keep cycle data until you delete it. Turning cycle tracking off stops reading, saving, reminders and Coach use, and keeps your data. Delete all cycle data in Cycle settings removes it from your account and can also remove the entries Logbook saved to Apple Health. Deleting your account removes it too, and the data export includes it.
Cycle data does not go to AI providers, advertising or analytics services unless you turn on Share cycle with Coach. With that permission, Coach receives a summary with your message: cycle day, phase, next period estimate, recent cycle lengths, and that day's flow, symptoms and energy. It never receives your fertile window or notes. You can turn sharing off at any time. Cycle reminders are local notifications with generic text. Predictions are estimates for training and wellbeing. They are not birth control or medical advice.
Coaching and notifications
We store your personal targets, training milestones, reflections, reminder preferences and notification delivery status. If you enable reminders, Expo and Apple process a device notification token and generic notification text. Detailed health information stays inside the signed-in app. You can pause reminders or turn them off in Settings. Automatic check-ins do not make AI requests.
Optional AI features
Coach, Quick Food and photo scanning require a separate permission in Settings. These features send your messages, voice recordings or photos and relevant training, nutrition and profile information through OpenRouter to the AI provider selected for the request. Coach includes Apple Health summaries and cycle data only if you share them with Coach. A Quick Food voice recording is stored on our servers only until it is written down, then deleted; the text stays with your food history. These providers process the request under their own terms and privacy policies. Do not include information about other people. You can withdraw AI permission in Settings and continue manual logging. Withdrawal stops new AI requests. It cannot recall data already sent.
Food data sources
Default and database food entries use reference composition data from the UK Composition of Foods Integrated Dataset (CoFID) and its 2021 workbook. Contains public sector information licensed under the Open Government Licence v3.0.
Default and database food entries also use USDA FoodData Central, including its SR Legacy archive, Foundation Foods and the FNDDS survey foods. USDA FoodData Central data are in the public domain.
Barcode results come from Open Food Facts, available under the Open Database License (ODbL). When you scan a barcode, your browser or device sends the barcode number to Open Food Facts to find the product.
Service providers and payments
Convex stores application data. Cloudflare R2 stores backed-up check-in photos. Clerk manages sign-in with Apple and Google. Resend sends the waitlist launch email and the Logbook emails you turn on. Vercel hosts the web app and provides website analytics. Sentry receives error reports and performance traces. Expo provides native builds and updates. Apple handles App Store payment information. RevenueCat processes a Logbook account identifier, store receipts and subscription status. We do not receive your full card details. These services can process data outside the UK. Contact us for information about applicable transfer safeguards.
Creator referrals and affiliate payouts
If you use a creator code or referral link, we process the code, its source (such as a link, web sign-up, the waitlist or code entry), the referring creator, the account that used it, and the time of each code you apply or remove. The first payment credits the code you applied most recently in the 30 days before it. A code saved with your waitlist address is applied when you create your account with that address. Attribution can change before your first payment and then locks, including when no code qualifies. We link the decision to the App Store subscription so that its later payments stay with the same creator if you move it to another account. A creator code does not change your price or give you access to a feature.
For eligible purchases, we process purchase and commission records such as the store transaction identifier, plan, store, country, normalized USD price, tax and store-commission fields, commission amount, holdback or release status, refunds, clawbacks and payout reconciliation. We also process creator contact, payout-method, tax and invoice information when a creator joins the affiliate program or receives a payout. We use this information to calculate, review, pay and document commissions, prevent fraud, answer disputes and meet accounting or legal duties.
Creator dashboards show aggregate link opens, accounts using a code, paying-customer counts, balances and payout statements. They do not show a referred customer's name, email, account identifier, training, nutrition, health information or other app content. Referral landing pages count link opens in aggregate by creator and UTC day. Known link previews and bots are not counted, but some can still be. Opening a creator link does not set a cookie. If you then choose to sign in or create an account from that link, the website sets a first-party cookie for up to 1 day. It holds only the creator code and is used only to add that code to your account after sign-in. We remove it once the code is on your account. We do not use an advertising tracker for attribution. See our cookie policy.
We keep a revenue record of purchases, renewals and refunds from our payment provider and Apple (store transaction identifiers, plan, price, tax and store-fee estimates) to reconcile payments and commissions. We keep the raw payment-provider event for up to 120 days after processing. If a customer deletes an account, we remove the referral association and its code history, detach the customer account identifier from commission and revenue records, and remove processed raw payment events linked to the account. An event not yet processed keeps its payload until it is processed, so a refund in it still applies, and is then removed within 120 days. Ledger, payout, tax, security and dispute records, and aggregate click rows, may remain for accounting, fraud prevention or legal obligations. We delete or anonymise those records when they are no longer needed. Creators can request access, correction or deletion of their own affiliate information, subject to records we must keep.
Error reports and performance
The iPhone app, the website and our backend use Sentry to report errors. Reports can include error messages, stack traces, the app or website version, and device or browser details. The Sentry SDKs are configured not to send default personally identifying information. A report can include your Logbook account ID. This is an opaque identifier. It does not contain your name or email. Error context can still contain technical data.
The iPhone app and the website also send performance traces to Sentry for a sample of activity: about 20% in the iPhone app and 10% on the website. Traces record how long screens, network requests and app operations take. We use error reports and traces to find and fix faults and slow screens. We do not use them for advertising.
Usage events
The iPhone app and the web app record a small set of usage events, such as onboarding steps, opening Coach or Quick Food, paywall views, purchase results and share-card shares. Each event holds the event name, a few related details, the platform, the app build and the time. We store these events with your account in Logbook's own database. We use them to learn which features people use and where setup or purchases fail. We do not sell these events or share them with advertising networks. We delete them when you delete your account.
Storage and deletion
We keep your account content while your account is active. Settings provides account deletion. This removes your sign-in credentials and starts deletion of your personal app records and private catalog. Shared household catalog entries remain for other household members. Service backups and payment or security records may remain where needed for recovery or legal obligations. Deletion does not cancel an Apple subscription. Cancel it through Apple separately. Check-in photos stay until you delete them or your account, or until 30 days after Pro ends.
Your choices and rights
You can edit or remove records in the app. Contact support to request access, an export, correction, restriction or deletion of your personal data, or to raise a privacy concern. Depending on the circumstances, you can also object to processing, ask for data portability and withdraw consent without affecting the lawfulness of processing before withdrawal. We may need to verify your identity. You can also complain to the UK Information Commissioner at ico.org.uk. Logbook is intended for adults aged 18 or older.
Device storage
We use authentication cookies and secure device storage to keep you signed in. Local app storage can hold settings, unfinished drafts, and queued sets awaiting sync. See our cookie and device storage policy for more detail. We do not sell your personal information or use advertising trackers.
Changes to this policy
We update this page when our data practices change. The date at the top shows the latest update. We will seek new permission where a change requires it.