Privacy Policy

Prepdex Holdings LLC (“Salt,” “we,” “us,” or “our”) operates the Salt application and website at usesalt.app (collectively, the “Service”). This Privacy Policy explains what information we collect, how we use it, and the choices you have.

For a plain-English explanation of how the encryption and key custody actually work, see our Privacy & Security page. This document is the formal version.

Our Approach to Privacy

Salt is designed around a principle that we think matters: the company that builds your health tracking tool should not be able to read your health data.

To achieve this, Salt encrypts your tracked health information on your device before it leaves. This includes compounds, doses, schedules, bloodwork values, vials, goals, notes, and progress photos. Our servers store this information in encrypted form that we cannot read.

We can see metadata about your account (your email address, when you signed up, your subscription status) and operational data needed to run the Service. We cannot see the substance of your protocols.

This architecture is deliberate. It means we cannot recover your encrypted data if you lose access to both your synced encryption key (described below) and your recovery phrase. It also means we cannot use your health data for any purpose, including improving the Service. The tradeoff is worth it.

Information We Collect

1.1 Account and Identity Information

Salt is passwordless. You sign in with Sign in with Apple or Sign in with Google. We do not create or store a password for you, and your Apple or Google credentials never reach our servers.

From your social sign-in we receive:

The email address associated with your Apple ID or Google account (which may be an Apple “Hide My Email” relay address if you choose that option at sign-in)
A provider-issued user identifier that Salt uses to recognize you on return visits
The date and time you created your Salt account

This identity information is held in our authentication system. It is not encrypted with your client-side master key because we need to use it to authenticate you, send you account emails, and provide the Service.

1.2 Subscription and Billing Information

When you start a trial or subscribe to Salt, we record:

Subscription plan, status, trial dates, and renewal/expiration dates
The platform your subscription is billed through (Apple in-app purchase on iOS)
A platform-specific customer or subscription identifier provided by the billing platform

Salt does not see, store, or process your payment card details. iPhone purchases are handled by Apple through the App Store. Creator-link web trials use Stripe to collect and store the card required for renewal; Salt receives only the subscription and billing status needed to provide the service.

We use RevenueCat as our subscription-state intermediary for iOS in-app purchases. RevenueCat receives the App Store purchase event from Apple and notifies our servers of changes to your subscription state.

1.3 Your Tracked Health Data (Encrypted)

When you use Salt to track your protocols, we receive and store the following categories of information only in encrypted form that we cannot read:

Compounds you track (names, classes, doses, schedules, and titration steps)
Vials, inventory, concentrations, and reconstitution details
Logged doses, dose history, and skip reasons
Bloodwork values, reference ranges, and trends
Goals, side-effect observations, and personal notes
Progress photos

Encryption keys are derived from material available only to your devices. We do not have access to your master key. See section 4 (“Data Security”) below for the details.

1.4 Apple Health Data (Encrypted)

If you grant Salt permission, the iOS app reads selected metrics from Apple Health (such as body weight, body composition, sleep, and other vitals you opt in to). This data is read into the app on your device and encrypted under your master key before it is written to our servers. We do not cache an unencrypted copy of your Apple Health data on our servers. You can revoke Apple Health access at any time in iOS Settings.

1.5 Bloodwork PDFs (Parsed Locally, Not Stored)

When you import a Quest or LabCorp lab PDF, the PDF is parsed entirely on your device by a local parser. Extracted values are encrypted with your master key before being saved to our servers. The PDF itself is never uploaded, stored, or sent to any third party or AI service.

1.6 Anonymized Diagnostics and Product Analytics

To keep the Service reliable and understand whether key features are working, Salt collects two limited kinds of anonymous information:

Crash reports through Sentry, which help us identify and fix technical problems.
Product analytics through PostHog, limited to specific lifecycle events such as opening the app, signing up, starting a trial, completing a purchase, or importing bloodwork.

This information is tied to a random identifier created on your device, not to your Salt account, email address, or protocol. Salt does not record your screen, capture what you type, or automatically track everything you do in the app. Automatic safeguards remove fields that could contain health or account information before an event is sent.

You can turn both types of telemetry off at any time in the app under Settings → Privacy → “Help improve Salt”, effective immediately and without restarting the app. This is also disclosed on our App Store privacy label under “Data Not Linked to You.”

Superwall displays subscription offers and receives paywall views, button interactions, purchase outcomes, and an anonymous pricing-experiment group. We do not send it your Salt account identity, health or treatment data, free text, or ad attribution. Settings → Privacy → Help improve Salt turns off Superwall event tracking.

1.7 Marketing Website Analytics (usesalt.app)

The marketing website at usesalt.app uses PostHog for basic audience measurement. We collect only:

The pages you view and when you leave them
The website that referred you, when your browser provides it
Campaign tags included in the link you followed

The site does not record your screen, typing, form contents, copied text, or clicks within a page. We do not connect marketing-site visitors to their Salt accounts.

1.8 Advertising Measurement

Salt uses limited advertising measurement to understand whether an ad led to an install, trial, or subscription. This is kept separate from product analytics and cannot receive information from your encrypted vault.

If you grant Apple’s App Tracking Transparency permission:

Meta and TikTok may receive an install, trial start, or subscription start, a random event identifier, device identifiers, and technical information such as your IP address, time zone, device model, operating system, app version, and tracking-permission status.
OpenAI may receive one event indicating a genuinely new installation, plus a random event identifier used to prevent duplicate reporting. Salt sends this event through its server so the credential used to contact OpenAI is never included in the app. The event is marked as opted out of future user-level personalization.

OpenAI does not receive your device advertising identifier from Salt. None of these advertising platforms receives your Salt account email or user ID, PostHog analytics ID, plan, price, or anything from your encrypted vault—including compounds, doses, schedules, bloodwork, Apple Health data, goals, notes, side effects, or photos. Salt does not use customer-list uploads, fingerprinting, or probabilistic matching.

If you decline Apple’s tracking permission, Salt sends no user-level advertising event to Meta, TikTok, or OpenAI. Apple’s privacy-preserving systems may still provide aggregated campaign measurement. You can change this choice in iPhone Settings → Privacy & Security → Tracking.

1.9 Communications

If you contact us for support, we keep a record of your message and our response. This helps us resolve issues and improve the Service.

How We Use Information

We use the information we collect to:

Provide, maintain, and improve the Service
Authenticate your account and protect against unauthorized access
Process subscriptions, trials, and renewals
Respond to your questions and provide customer support
Send service-related emails (account confirmations, subscription notices, security alerts, important changes to the Service)
Detect and prevent fraud, abuse, and security threats
Analyze aggregate, anonymized usage to improve the Service
Measure approved advertising campaigns within the limits in section 1.8
Comply with legal obligations

We do not:

Sell your data to anyone
Use your tracked health data to train artificial intelligence or machine learning models
Show advertising inside the Salt app
Share your tracked health data, account identity, or product-analytics identifier with advertising platforms
Run user-level advertising measurement unless you grant Apple’s tracking permission
Read or analyze your tracked health information (we cannot — it is encrypted)
Build a clinical record on you or share data with insurers, employers, or health systems

We share information only with the parties described below, and only for the purposes described.

Service Providers

We use third-party providers to operate the Service. Each receives only the information it needs to perform its function:

Supabase — backend infrastructure, database, and authentication. Stores your account information and health data that has already been encrypted on your device. It cannot decrypt the health-data fields.
Apple — Sign in with Apple identity verification; App Store in-app purchase billing for iOS subscribers.
Google — Sign in with Google identity verification.
RevenueCat — subscription-state intermediary for iOS in-app purchases. Receives App Store purchase events and reports subscription state back to Salt.
Stripe — card processing for creator-link web trials and payout processing for creators in the Salt referral program (Stripe Connect). Stripe receives the payment information needed to process web billing and the limited account/tax information required to pay creators.
Sentry — crash reporting. Receives technical error data with health-data-shaped fields removed by the on-device scrubber described above.
PostHog — product analytics. Receives the limited, anonymized iOS-app lifecycle events described in section 1.6 and the pageview/referrer/UTM data from the marketing site described in section 1.7.
Superwall — subscription paywall display and the paywall activity described in section 1.6.
Meta and TikTok — advertising measurement. When you grant Apple’s tracking permission, receive the events, device identifiers, and technical information described in section 1.8. They do not receive your tracked health data.
OpenAI — advertising measurement. When you grant Apple’s tracking permission, receives only the one-time install event and random per-event ID described in section 1.8, with no Salt account, device-advertising, analytics, or health identifier.
Netlify — marketing-website hosting (usesalt.app). Receives standard web request data (IP address, user agent, requested URL) as part of serving the site.

We have contracts or terms with these providers requiring them to handle your information consistent with this Privacy Policy and applicable law.

Legal Requirements

We may disclose information when required by law, such as in response to a valid subpoena, court order, or government request. We will push back on overbroad requests and notify you when legally permitted.

Because we cannot decrypt your health data, any legal request seeking it would receive only encrypted data that cannot be read.

Business Transfers

If Salt is involved in a merger, acquisition, or sale of assets, your information may be transferred as part of that transaction. We will notify you before your information is transferred and becomes subject to a different privacy policy.

How Long We Keep Information

Account data. We keep your account information for as long as your account is active.

Encrypted health data. We keep your encrypted health data for as long as your account is active. We cannot read it, but we store it so you can.

Account deletion. When you delete your account, we purge your encrypted health data and personal account information from our active systems. Residual copies may remain in routine backups for a short period before they are cycled out. Account deletion is permanent and cannot be reversed.

Billing records. We retain billing records for as long as required by applicable tax and accounting laws (typically seven years in the United States).

Support communications. We retain support communications for up to two years to help us improve the Service.

Aggregated, anonymized analytics. Aggregated, non-identifying analytics may be retained indefinitely for product-improvement purposes.

Your Rights and Choices

Access and Export

You can access your data at any time through the Service. Because your health data is encrypted on your device, the app is the most reliable place to view it. We do not currently offer a one-tap “export everything” download; building that export is on our roadmap.

Correction

You can correct any information you have entered into the Service at any time through the app.

Deletion

You can delete individual entries through the app, or you can delete your entire account from the Service. Account deletion is permanent.

Subscription Cancellation

You can cancel your subscription at any time through the App Store: iOS Settings → Apple ID → Subscriptions.

Telemetry Opt-Out

You can disable crash reporting and product analytics at any time in Settings → Privacy → “Help improve Salt” inside the app.

Advertising Measurement

Apple’s App Tracking Transparency choice controls user-level advertising measurement. If you decline, Salt does not send Meta, TikTok, or OpenAI a user-level advertising event. You can review or change the permission in iPhone Settings → Privacy & Security → Tracking.

Marketing Emails

If we ever send you marketing emails (we currently do not), you can opt out using the unsubscribe link in any such email. We will still send service-related emails (account confirmations, billing notices, security alerts) because they are necessary for the Service.

Cookies

The Salt app does not rely on third-party cookies. The marketing website at usesalt.app uses minimal first-party storage for site functionality and for the narrow PostHog pageview analytics described in section 1.7. We do not run third-party advertising cookies, cross-site trackers, or session-replay scripts on the marketing site.

Rights for Specific Jurisdictions

California Residents

If you are a California resident, you have additional rights under the California Consumer Privacy Act (CCPA) and California Privacy Rights Act (CPRA):

Right to know what personal information we have collected about you
Right to delete personal information we have collected from you
Right to correct inaccurate personal information
Right to opt out of the sale or sharing of personal information (we do not sell or share personal information)
Right to limit use of sensitive personal information (we do not use sensitive personal information beyond providing the Service)
Right to non-discrimination for exercising your rights

To exercise these rights, contact us at support@getjoust.app. We will verify your identity before fulfilling requests.

European Economic Area, United Kingdom, and Similar Jurisdictions

If you are located in the European Economic Area, the United Kingdom, or a jurisdiction with similar data protection laws, you have rights under applicable law including:

Access to your personal data
Rectification of inaccurate personal data
Erasure (right to be forgotten)
Restriction of processing
Data portability (within the limits described under “Access and Export” above)
Objection to processing based on legitimate interests
Withdrawal of consent where processing is based on consent
Lodging a complaint with your local data protection authority

The legal bases for our processing of your personal data are:

Performance of a contract — to provide the Service you’ve signed up for
Legitimate interests — limited usage data to improve the Service and ensure its security
Consent — for marketing communications (if we ever send them) and for any optional analytics features
Legal obligations — to comply with tax, accounting, and other laws

Salt is operated from the United States. By using the Service from outside the United States, you understand that your information will be transferred to and processed in the United States.

To exercise your rights, contact us at support@getjoust.app.

Children’s Privacy

The Service is not intended for anyone under 18. We do not knowingly collect information from individuals under 18. If we learn that we have collected information from someone under 18, we will delete it and terminate the account.

If you believe we have collected information from someone under 18, please contact us at support@getjoust.app.

Data Security

We protect your information using:

Encryption on your device. Your tracked health information is encrypted before it leaves your device. Our servers store only encrypted data that Salt cannot read.
Keys controlled by your devices. The key needed to unlock your health data is never sent to Salt in a readable form. On iOS, it can sync securely across your Apple devices through iCloud Keychain.
A 24-word recovery phrase. Your recovery phrase provides a separate way to restore access if device syncing is unavailable. Salt never receives the phrase in readable form and cannot recreate it for you.
Secure connections and storage. We use encryption while information is being transmitted and while it is stored.
Account-level safeguards. Additional access controls ensure stored information is returned only to the signed-in account that owns it.
Restricted internal access and regular security reviews.

No security system is perfect. If we become aware of a security incident affecting your information, we will notify you as required by applicable law.

Changes to This Privacy Policy

We may update this Privacy Policy from time to time. When we make material changes, we will notify you by email and post the updated policy on our website. The “Last updated” date at the top of this policy will reflect the most recent revision.

For changes that materially expand how we use your information, we will provide notice and, where required by law, obtain your consent.

Contact Us

For questions about this Privacy Policy or our privacy practices, contact:

Prepdex Holdings LLC Attn: Privacy support@getjoust.app

If you are in the European Economic Area or the United Kingdom and your concerns cannot be resolved by contacting us, you have the right to lodge a complaint with your local data protection authority.