Mainbeam
Last updated 19 September 2026
Mainbeam is an iPhone app that estimates a deer's antler score from a photo and calculates scores from tape measurements.
Mainbeam has no account, no server of its own, no ads and no analytics. Your bucks, photos and score sheets stay on your iPhone. A photo leaves your phone only if you allow Mainbeam to send it to Google's Gemini model for reading, and then only that photo is sent.
Your bucks, photos, score sheets, harvest tags and notes are stored in the app on your iPhone, together with your settings and the number of free photo scores you have left. We cannot see any of it.
The first time you score a photo, Mainbeam asks whether it may send photos to Google's Gemini API. If you agree, each photo you score is sent so Gemini can mark the ears, beams and tines and judge the buck's age from his body. Before a photo is sent, Mainbeam shrinks it and removes its location, date and camera details. Nothing else is sent: no name, no account and no device identifier. As with any internet request, Google can see the IP address the request comes from.
Google processes the photo under the Gemini API Additional Terms of Service, https://ai.google.dev/gemini-api/terms, and the Google Privacy Policy, https://policies.google.com/privacy. Mainbeam uses Google's paid service, under which Google processes the photo only to answer Mainbeam's request, does not use it to improve its products and keeps it only for a limited time to detect abuse. Google protects the photo at least as well as this policy describes.
You can say no when Mainbeam asks, or switch off "Find the antlers for me" in Settings at any time. With it off, no photo leaves your phone and you place the points yourself. A photo kept for later because there was no signal stays on your phone until you choose to read it.
The camera is used only while you photograph a buck. Photos you pick come through Apple's photo picker, so Mainbeam receives only the photos you choose and never your whole library. Saving a harvest tag image asks for permission to add it to Photos; Mainbeam cannot read your library.
Mainbeam never asks for your location. A county on a harvest tag is only what you type.
Payments are handled by Apple. Mainbeam uses RevenueCat to check whether your plan is active. RevenueCat receives the App Store's record of your purchases and a random ID the app creates on your iPhone; it does not receive your name, your email or your photos. RevenueCat's privacy policy: https://www.revenuecat.com/privacy
Mainbeam has no ads, no analytics and no crash reporting, and it does not track you across apps or websites. Its only third-party SDK is RevenueCat, for purchases.
Removing a buck or a sheet deletes its photos and scores from Mainbeam. Deleting the app deletes everything on your iPhone. We keep no copy of your bucks or photos. To have your purchase record deleted from RevenueCat, email us and we will ask RevenueCat to delete it.
Mainbeam is made for adult hunters and is not directed to anyone under 18.
If this policy changes, the new version will be posted at the same address with a new date.