Open Source Calorie Tracker

MIT License · iOS + Android · Updated September 14, 2026

Fud AI is a free, open source calorie tracker for iPhone and Android. The whole product — the SwiftUI iOS app, the Jetpack Compose Android app, and this website — is published under the MIT License on GitHub. You can read every network call the app makes, build it yourself, or fork it. The store versions are built from the same code.

Download on the App Store Download on Google Play

Why open source matters for a food tracker

A calorie tracker sees what you eat, how much you weigh, and often your health data. With a closed app you have to trust the privacy policy. With an open source calorie tracker you can check it: which servers the app talks to, what leaves the phone, how API keys are stored, and whether there is any analytics SDK hiding in the build. Fud AI's answer to each of those questions is in the repository, not just in marketing copy.

No in-app third-party analytics, advertising, or crash-reporting SDKs.
No Fud AI account and no Fud AI-operated cloud sync of your diary — data is local-first on your device.
API keys are stored in the iOS Keychain or Android EncryptedSharedPreferences (AES-256, Keystore-backed) and are never transmitted to us.
Security reports have a documented path in SECURITY.md, and the Privacy Policy spells out every optional network request.

What is in the repository

The fud-ai repository is a monorepo:

ios/ — the iPhone app in Swift 5 and SwiftUI (iOS 17.6+), including Apple Watch, widgets, Siri Shortcuts, and the Share Extension.
android/ — the Android app in Kotlin and Jetpack Compose (Android 8.0+), including Glance widgets and Health Connect.
web/ — this static marketing site and the small Cloudflare Worker behind optional features such as short meal-share links.
Store listing copy, contributing guide, code of conduct, and the MIT LICENSE file.

Both apps store detailed data locally (UserDefaults on iOS, DataStore Preferences on Android) and talk to AI providers, Open Food Facts, and platform health stores only when you trigger those actions.

Free and open source — not "open core"

There is no premium repository and no feature that exists only in a paid build. The free app on the App Store and Google Play includes the full tracker: multi-photo AI food scanning, barcode lookup, voice and text logging, 30+ nutrients, weight and body-fat tracking, optional water and fasting, a workout diary with an 877-exercise library, AI Coach chat, widgets, Apple Watch, and optional Apple Health / Health Connect sync.

AI analysis uses Bring Your Own Key, which is free forever: connect a free Google Gemini key, try OpenRouter's openrouter/free routing, or run Ollama locally. Fud AI supports 13 providers so you are never tied to a single vendor. On iPhone there is also an optional Plus/Pro hosted AI subscription for people who prefer not to manage keys; it is never required. Development is supported by an optional Tip Jar on iOS and Ko-fi on Android. Details are on the free AI calorie tracker page.

Open source app, your choice of AI

Open source stops at the app boundary for most AI products, because the model runs on someone else's servers. Fud AI lets you push that boundary as far as you want:

Fully local: point the app at Ollama on your own computer and run open-weight vision models — nothing leaves your network.
Open-weight via a provider: models such as Gemma, Qwen VL, and Llama Vision are available through supported providers and custom OpenAI-compatible endpoints.
Hosted frontier models: Gemini, OpenAI, Anthropic Claude, xAI Grok, Mistral, and more, each on your own key and under that provider's terms.
On-device fallback: on supported iPhones, Apple Intelligence can process eligible food descriptions locally as the final fallback.

Build it, fork it, contribute

Clone the repository, open ios/ in Xcode or android/ in Android Studio, and build. CONTRIBUTING.md explains the automated checks and how to submit a pull request. Bug reports and feature requests use GitHub issue templates: report an issue or request a feature. The MIT License lets you use, modify, and redistribute the code, including in your own projects, as long as the license notice is kept.

Frequently asked questions

Is Fud AI really open source?

Yes. The complete iOS app (Swift, SwiftUI), Android app (Kotlin, Jetpack Compose), and this website are published under the MIT License at github.com/apoorvdarshan/fud-ai. The store builds are made from that repository.

Is there a free open source calorie tracker with AI photo logging?

Fud AI is one. It is free, MIT-licensed, and logs meals from photos, voice, barcodes, or text using an AI key you own. Bring Your Own Key mode is free forever; a free Google Gemini key, OpenRouter's free routing, or a local Ollama model all work. See how the scanner works on the AI food scanner page.

Can I build Fud AI from source or install an APK?

You can clone the repository and build the iOS app with Xcode or the Android app with Android Studio. The official Android build is distributed through Google Play, so no separate APK download is needed for normal use.

Are the AI models open source too?

The app is open source; the AI model is whichever provider you configure. If you want open-weight models, Fud AI supports Ollama running locally plus open-weight vision models such as Gemma, Qwen VL, and Llama Vision through supported providers and custom OpenAI-compatible endpoints.

Does an open source calorie tracker still need an account or server?

Not with Fud AI. There is no Fud AI account and no Fud AI-operated cloud sync of your diary. Data is stored locally on your device, API keys stay in the iOS Keychain or Android EncryptedSharedPreferences, and only the requests you initiate — such as an AI analysis or a barcode lookup — leave the phone. The Privacy Policy lists each one.

Get the open source calorie tracker

Install from the stores, or star the repo and build it yourself. Wondering how an open source, BYOK tracker compares to subscription apps? Read Fud AI vs Cal AI.