Bring your own key
Paste a Gemini or OpenAI API key. You pay the provider directly, usually a fraction of a cent per photo.
Neutrino · AI meal logging for Android
Snap your plate.
Snap your plate.
Log your macros.
Neutrino is a free, open-source Android app for logging what you eat. Take a photo of your meal and Neutrino uses the AI model you choose (Google Gemini or OpenAI, with your own API key) to estimate its carbs, protein, fat and calories. You review the numbers, and Neutrino saves them to Health Connect as breakfast, lunch, dinner or a snack based on your local time.
- No account
- No ads or tracking
- Coming soon to Google Play
About Neutrino
What Neutrino does
Neutrino helps people track their nutrition without searching food databases or typing in every ingredient. It is made for anyone who wants to count carbohydrates or macros, including people managing their diet for health reasons.
With Neutrino you can:
- Photograph a meal and get an itemised estimate of carbohydrates, protein, fat and calories.
- Review and correct each food and portion before anything is saved.
- Save the meal to Health Connect, labelled as breakfast, lunch, dinner or snack from your time zone, so it appears in Google Health, Fitbit and other apps you allow.
- Log water intake in one tap.
- Back up your settings and meal history, encrypted, on your device and optionally in your own Google Drive.
How it works
From photo to logged meal in seconds
No searching food databases or weighing everything. Take a picture, fix anything that looks off, and save.
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Snap
Take a photo of your plate, or pick one from your gallery if you forgot earlier.
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AI estimates
Your chosen model identifies each food and estimates portions, carbs, protein, fat and calories.
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You review
Adjust portions in a tap. The meal type is picked from your local time, and you can change it.
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Saved
The meal is written to Health Connect, so it appears in Google Health, Fitbit and other apps you allow.
Privacy by design
We never see your data, because we don't have servers
Neutrino has no backend, no accounts and no analytics. Your phone talks directly to the AI provider you picked and to your own Health Connect.
- Your key stays on your phoneEncrypted with Android Keystore. Never sent to us.
- No tracking, ads or crash reportingNothing phones home. Read the code to check.
- Backups belong to youEncrypted on your device, stored locally or in your own Google Drive.
Your phoneNeutrino runs entirely here
meal photo, with your key
Your AI providerGoogle Gemini or OpenAI, under your account
nutrition you approved
Health ConnectOn-device, and you control which apps can read it
Neutrino serversDon't exist. Nothing is sent to us.
Features
Small app, carefully built
Everything you need to log meals fast, and nothing that gets in your way.
Pick your model
Neutrino lists the vision-capable models your key can use, so you can trade speed, cost and accuracy.
Knows what meal it is
Breakfast, lunch, dinner or snack, chosen from your time zone and your own meal windows.
Understands local food
Tell it your cuisine, like Bangladeshi, Indian or Mexican, for better recognition of bhaat, dal, biryani and more.
Water too
Log a glass in one tap. Hydration goes to Health Connect alongside your meals.
Open source, GPL-3.0
Every line is public. Audit it, build it yourself, or contribute a new AI provider.
Backups
Don't lose a thing, even if you reinstall
Like the chat apps you already use: an encrypted local backup is created on day one. Connect your Google account to keep a copy in your own Drive, daily, weekly or monthly.
- Encrypted before upload
- Private app folder in your Drive
- Restore on a new phone
FAQ
Questions, answered
Is Neutrino free?
Yes. The app is free and open source under GPL-3.0. The only cost is what your AI provider charges for your API usage, usually a fraction of a cent per photo, billed to your own account.
Which AI providers are supported?
Google Gemini and OpenAI at launch. Providers are plug-ins, so more can be added by the community.
Do you see my photos or health data?
No. Neutrino has no servers. Photos go straight from your phone to the AI provider you chose, under your account and their terms. Nutrition is saved to Health Connect on your device.
Some providers' free tiers may use submitted content to improve their services. Check your provider's terms if that matters to you.
How accurate are the estimates?
Photo-based estimates are approximate. Portion size is the hardest part to judge from a picture. That's why Neutrino always shows you the numbers to review before saving. Neutrino is not a medical device. Don't use it as the sole basis for medical decisions such as insulin dosing.
Does it work on iPhone?
Not yet. Neutrino is built for Android and Health Connect. Android 14 and newer include Health Connect; on older versions you can install it from Google Play.
What happens if I uninstall or clear the app's data?
Meals you've already saved stay in Health Connect. Your settings, history and API key can be restored from your encrypted local backup or your Google Drive backup.
What can Neutrino access in my Google Drive?
Only a private, hidden folder that belongs to Neutrino. It cannot see or change any of your other files, and you can revoke access at any time from your Google Account settings. See the Privacy Policy for details.
Built in the open
Star the repo to follow along, report issues, or help add providers and cuisines.