prodromal.ai

Prodromal — Privacy Policy

Last updated: April 19, 2026 Effective: April 19, 2026

Summary (the short version)

• Your health data never leaves your iPhone except in end-to-end encrypted form
• We don’t sell your data. We don’t run ads. We don’t share with brokers
• You can delete everything any time from Settings → Delete Account
• Questions: privacy@prodromal.ai

Who we are

Prodromal (“Prodromal”, “we”, “us”, “our”) is operated by Jonathan Huang, a sole proprietor registered in Singapore. Prodromal is a consumer iOS app that coaches users through the prodromal phase of illness.

What we collect

Health data (via Apple HealthKit)

With your explicit permission, Prodromal reads the following from Apple Health:

• Heart rate variability (HRV, SDNN)
• Resting heart rate
• Respiratory rate
• Body temperature
• Blood oxygen saturation (SpO₂)
• Heart rate

How it’s used: to compute your personal baseline and detect early-warning drift 24–36 hours before symptoms.

Where it lives: all HealthKit readings are processed on your device. Raw HealthKit data is never transmitted to our servers.

Symptom and episode data (entered by you)

When you log symptoms, take a check-in, or resolve an illness, the following is stored locally on your device via Apple’s SwiftData framework:

• Symptom type and severity
• Free-text notes
• Trigger contexts (stress, travel, etc. if selected)
• Protocol action completions
• Peak severity on resolution

Where it lives: on your device only, in an iOS-managed local database. It is backed up via your iCloud backup if you have that enabled (controlled entirely by you).

AI chat messages

When you use the chat feature to ask Prodromal questions, your message is sent to Anthropic (claude.ai) via their API for processing. Prodromal does not retain copies of your chat messages server-side.

Anthropic’s data processing terms apply to those messages. As of the current date, Anthropic does not train on API inputs. See anthropic.com/privacy.

Account data

We do not require an account for core functionality. If you subscribe to Prodromal Pro or Family:

• Your subscription is managed entirely by Apple (App Store). We do not receive your credit card, email, or Apple ID.
• We receive only a subscription receipt confirming your entitlement tier.

Analytics (anonymous, aggregated)

We use analytics software to understand how people use Prodromal. We track events like:

• First open
• Onboarding completion
• Episode start / resolve
• Paywall view / conversion
• Chat message sent (count only, not content)

What we do not track:

• Your health data values (HRV, temperature, etc.)
• Your symptom content
• Your chat message content
• Your name, email, phone number, or Apple ID

Analytics events are tied to an anonymous device-scoped identifier. You can opt out in Settings → Privacy → Analytics.

Crash reports

We use Firebase Crashlytics to capture crash reports. Crash reports include:

• iOS version
• Prodromal version
• Anonymized device model
• Stack trace at time of crash

No personal data or health data is included.

What we don’t do

• We don’t sell your data to anyone, ever
• We don’t share your data with advertisers
• We don’t share your data with data brokers
• We don’t use your data to train AI models
• We don’t request tracking permission under App Tracking Transparency — we don’t track you across apps

Apple Family Sharing (Family plans)

If you subscribe to Prodromal Family, up to 5 Apple Family members can access Pro features. Each member’s health data remains entirely private to them — no one on your family plan can see anyone else’s data, including you. The Family plan only shares the subscription entitlement.

Your rights

You can:

• Export all your data: Settings → Export My Data → generates a JSON file
• Delete all your data: Settings → Delete Account → wipes everything from your device and revokes analytics ID
• Revoke HealthKit access: iOS Settings → Privacy & Security → Health → Prodromal → toggle off
• Cancel subscription: iOS Settings → Apple ID → Subscriptions → Prodromal

GDPR / Singapore PDPA / California privacy rights

If you’re in the EU, UK, Singapore, or California, you have additional rights:

• Right to access: we’ll send you a copy of all data we hold about you within 30 days
• Right to erasure: we’ll delete everything within 30 days
• Right to data portability: your export includes all personal data in JSON
• Right to object: contact privacy@prodromal.ai

Children

Prodromal is not intended for users under 13. If we discover an under-13 account, we delete it.

Changes to this policy

We’ll email subscribers and show an in-app notice at least 30 days before any material change.

Contact

• Privacy: privacy@prodromal.ai
• Support: support@prodromal.ai
• Legal entity: Jonathan Huang, Singapore