Sneezecast privacy policy
Last updated: October 20, 2026
Sneezecast is a pollen forecast that learns which pollen affects you from a diary you keep on your iPhone. This policy explains what the app keeps on your phone, what it sends, and to whom. In short: your symptoms, medicine, notes and triggers never leave your phone.
What stays on your phone
Everything you log stays in the app's storage on your device and is never sent to us or to anyone else:
- your daily check-ins (how you felt, any medicine you took, what you tried that day such as closing the windows, where you had symptoms, and notes);
- the months you marked as your worst, and a place you check for a trip;
- your profiles (for example a child's name) and the plants you marked as yours;
- your personal trigger model, your allergy fingerprint and your plant sensitivities, which are calculated on the phone;
- readings from an Awair air monitor, which the app reads over your home Wi-Fi without going through the internet;
- your notification settings. Morning and evening notifications are scheduled on the phone itself.
When you share your allergist report (PDF) or your fingerprint image, it goes only where you choose to send it, with the iOS share sheet. Sneezecast does not receive a copy.
What leaves your phone
Approximate location, to fetch the forecast. To show the pollen and air quality where you are, the app sends a coarse area to the Sneezecast server: your position rounded on the phone to a grid of about 28 km (0.25°). Your exact location is never sent to Sneezecast. If you type a ZIP code instead, iOS looks it up with Apple's geocoding service, and the app asks the same service for the neighbourhood name it shows; Apple's privacy policy covers those requests. The server asks Google's Pollen API and the EPA's AirNow service for that area's forecast and keeps the answer in a short-lived cache so that nearby users share it. A place you check for a trip is sent the same way, as its rounded area only. With Sneezecast Plus, the server also asks the US National Weather Service for the area's hourly wind and rain forecast, to work out the best hours to be outside. Your IP address is used only to limit how many requests one device can make in an hour; that counter expires after an hour.
Usage and crash reports. If analytics is switched on in the build, the app sends PostHog a few anonymous events (for example "onboarding completed", "check-in logged", "paywall viewed") and reports of crashes, tied to a random identifier for the app install. These events never include symptoms, medicine, notes, the plants you marked, or your location. The app does not use advertising identifiers and does not track you across other companies' apps or websites.
Purchases. Subscriptions are bought through Apple; Sneezecast never sees your payment details. The app uses RevenueCat to check whether your Sneezecast Plus subscription is active. RevenueCat receives a random app user identifier and your App Store purchase receipts.
Who receives data
| Recipient | What | Why |
|---|---|---|
| Sneezecast server (hosted on Vercel, cache on Upstash) | Approximate area, IP address for rate limiting | Fetch and cache the forecast |
| Google Pollen API | Approximate area (from our server) | Pollen forecast |
| EPA AirNow | Approximate area (from our server) | Air quality |
| US National Weather Service | Approximate area (from our server), with Sneezecast Plus | Hourly wind and rain |
| PostHog | Anonymous usage events and crash reports | Improve the app and fix crashes |
| RevenueCat | Random app user identifier, App Store receipts | Unlock Sneezecast Plus |
| Apple | Your purchase; a ZIP code or position to look up a place name | Payments; place names (iOS geocoding) |
We do not sell your data, and we do not share it for advertising.
Children
Sneezecast is meant for adults. A parent can add a child's profile; everything about it stays on the parent's phone like the rest of the diary.
Your choices
- Delete everything: Settings → Delete all data removes every check-in, profile, place and setting from the phone. Deleting the app does the same.
- Location: you can type a ZIP code instead of sharing your location, and change the place at any time.
- Notifications: turn them off in iOS Settings → Sneezecast → Notifications.
- Analytics and purchase records: write to us and we will ask PostHog and RevenueCat to delete the records tied to your app identifier.
Medical disclaimer
Sneezecast offers decision support, not medical advice. It does not diagnose or treat any condition. Talk to your doctor about your allergies and your medicine.
Contact
Questions or requests about this policy: support@matterdevelopment.com.
If this policy changes, the new version will be posted at this address with a new date.