Your data stays on your device.

Castrel is built on a simple principle: we don't collect or sell your personal information. An optional account lets you save preferences across devices. It's never required to use the app.

Last updated: April 16, 2026 · Effective: April 16, 2026

1. Who we are

Castrel is a weather and travel planning app built by Alan Puthenchira. If you have any privacy questions, reach out at privacy@castrel.app.

2. What data Castrel handles

Here's a plain-English breakdown of every piece of data Castrel touches and where it goes:

Data	Where it lives	Who sees it
Liked places	On your device only	Only you
Calendar events	On your device only	Only you
Temperature preference (°C/°F)	On your device only	Only you
Theme & display preferences	On your device only	Only you
Last searched location	On your device only	Only you
Trip history (last 5 plans)	On your device only	Only you
Saved trip itineraries (signed-in users)	Stored securely on our servers	Only you + Castrel (never shared)
Email address (optional account)	Stored securely on our servers	Only you + Castrel (never shared)
Display name (optional account)	Stored securely on our servers	Only you + Castrel (never shared)
City name when you search	Sent to look up location, then discarded	OpenStreetMap (free public map service)
Your coordinates when fetching weather	Sent to get weather, then discarded	Weather services (see section 5)
Your trip request (destination + preferences)	Sent to generate your plan, then discarded	Claude AI by Anthropic (see section 5)
Venue names from trip plans	Sent to verify they exist, then discarded	Google Places API (see section 5)

3. Optional account

Castrel offers an optional Sign In feature. Creating an account is always free. It will never cost anything to sign up. An account is never required to use the app. All core features work without one. If you choose to create an account:

• Your email address and display name (first name, optional last name) are stored securely using Supabase, a trusted database platform
• Your email is used only to identify your account. We don't send marketing emails
• Your account lets us track how many trip plans you've generated (to manage free plan limits)
• If you're signed in, your trip itineraries are saved securely on our servers so you can access them across devices. You can delete any saved trip at any time
• You can delete your account at any time from within the app or by emailing privacy@castrel.app. Deletion is permanent and cannot be undone

4. How your settings are saved

All your personal data (liked places, saved events, preferences) is saved directly on your device. This means:

• It never leaves your device
• We have no access to it whatsoever
• Clearing your browser data or deleting the app removes it permanently
• It does not sync across your devices (unless you're signed in, coming soon)

If you are signed in, your trip itineraries are also saved securely on our servers using Supabase. This allows you to access your trips from any device. Deleting your account removes all server-stored trip data permanently.

5. Services Castrel connects to

To show you weather and plan trips, Castrel sends requests to a few well-known external services. None of them receive your name, email, or anything that identifies you personally.

• OpenStreetMap / Nominatim: A free, open-source map service. When you search for a city, Castrel asks it to look up coordinates. Only the city name is sent. See their Privacy Policy.
• National Weather Service (NWS): The US government's free weather service. Used for US locations. Only your coordinates are sent.
• Open-Meteo: A free international weather service. Used for locations outside the US. Only your coordinates are sent. See their Terms.
• Google Weather API: Used for weather alerts (storms, floods, wind advisories) and extended forecasts. Only your coordinates are sent. Requests are proxied through our server so your API key is never exposed. See Google's Privacy Policy.
• Claude AI by Anthropic: Powers the AI trip planner. When you generate a trip plan, your destination and preferences are sent to Claude to create your itinerary. This is not stored, not shared, and not used to train any AI model. See Anthropic's Privacy Policy.
• Supabase: Used to store optional user accounts securely. If you sign in, your email is stored in Supabase's encrypted database. See Supabase's Privacy Policy.
• Google Places API: Used to verify that venues suggested by the AI trip planner are real businesses. Only venue names and city names are sent. No personal data is shared. See Google's Privacy Policy.
• Discord (internal notifications): When you create or delete an account, a notification containing your email address is sent to a private, access-restricted channel used only by the Castrel development team for operational monitoring. This data is never shared publicly or used for marketing.

6. Location access

Castrel may ask for permission to use your device's location so it can automatically show you local weather. This is entirely optional. You can type any city manually instead. If you allow it:

• Your location is only used to fetch local weather in real time
• It is stored temporarily on your device to avoid repeated requests
• It is never sent to our servers
• You can turn it off at any time in your iPhone or browser settings

7. No tracking, no ads

Castrel does not use any form of advertising, tracking, or analytics that identifies you. Specifically, we do not use:

• Ads or ad networks
• Tools that track what you tap or how you use the app
• Tools that try to identify you across other websites or apps
• Any form of data collection for marketing purposes

We do not sell, rent, or share your data with anyone for any commercial purpose.

8. Children's privacy

Castrel is a general-purpose weather and travel app suitable for all ages. We do not collect personal information from anyone, including children. The optional Sign In feature requires users to be 13 or older. If you believe a child under the age of 13 has created an account, please contact us at privacy@castrel.app and we will delete it immediately.

9. Deleting your data

You are in full control of your data:

• Liked places & events: Remove them directly within the app at any time
• Browser data: Go to your browser settings and clear data for castrel.app
• iPhone app: Delete the Castrel app to wipe all locally stored data
• Account & email: Tap Sign In and use the "Delete my account" button to permanently delete your account instantly. If the button is unavailable, email privacy@castrel.app and we will delete your account within 7 days.
• When you delete your account, all your data (liked places, trip plans, and profile) is deleted immediately. We retain only your email address and deletion date for 90 days for fraud prevention and legal compliance, after which it is permanently deleted.
• ⚠️ DELETED ACCOUNTS CANNOT BE RECOVERED. IF YOU WANT TO USE CASTREL AGAIN AFTER DELETION YOU CAN CREATE A NEW ACCOUNT WITH THE SAME EMAIL. IT WILL START FRESH WITH NO PREVIOUS DATA.
• If you change your mind within 7 days of requesting deletion, email us at privacy@castrel.app and we may be able to cancel the request. Some data may or may not still be available depending on when you contact us.

10. Changes to this policy

If we update this policy, we'll change the "Last updated" date at the top. We'll never make changes that reduce your privacy without being transparent about it.

Why we keep saying "your data is your data"

In this day and age, people who want to remain anonymous online have to go through great lengths to do so: VPNs, burner emails, ad blockers, cookie rejections. It's exhausting.

With Castrel, none of that is necessary. We have no use for your personal data. We're a weather and travel planning app: we need to know what city you want weather for and what you want to do there. If you choose to create an account, we ask for an email to manage that account and so your trips and saved places can be accessed from any of your devices. We never use it to track you. We never link your email to your searches, your weather lookups, or your trip plans. We don't build profiles. We don't run ads. We don't have a data business on the side.

Most weather apps are free because your data is the product. Castrel is different.

So when you see "🔒 YOUR DATA IS YOUR DATA" in the footer, that's what it means. It's not a legal disclaimer. It's just true.