Fud AI vs Cal AI

Honest comparison · Updated September 14, 2026

Cal AI and similar apps made "snap a photo, get the calories" mainstream. Fud AI does the same core job — photo, voice, barcode, and text logging with AI nutrition estimates — but with a different model: it is free forever with your own AI key, open source under the MIT License, local-first with no required account, and has no ads. This page lays out the differences plainly, including where a paid hosted app may suit you better.

Download on the App Store Download on Google Play

The short version

Price: Fud AI's core tracker is free with no subscription; Cal AI-style apps typically charge a recurring subscription after a trial.
AI: Fud AI runs on a key you own from any of 13 providers (a free Gemini key works); hosted apps use a model they choose and pay for on your behalf.
Code: Fud AI is MIT-licensed open source; most competitors are closed source.
Data: Fud AI is local-first with no required account; hosted apps usually store your diary on their servers.
Ads and tracking: Fud AI has none — no ads, no in-app analytics SDKs.

Side-by-side

The Fud AI column describes the current App Store and Google Play release. The right-hand column describes how Cal AI-style hosted AI calorie apps generally work; check any specific app's own listing and privacy policy for current details.

Feature	Fud AI	Cal AI-style paid AI trackers
Price	Free forever with Bring Your Own Key. Optional Tip Jar on iOS and Android. Optional Plus/Pro hosted AI plans on iPhone and Android if you want them.	Typically a monthly or yearly subscription, often after a short free trial.
Source code	Open source, MIT License, on GitHub.	Typically proprietary / closed source.
Who runs the AI	You choose: Gemini, OpenAI, Claude, Grok, OpenRouter, Together AI, Groq, Hugging Face, Fireworks AI, DeepInfra, Mistral, Ollama (local), or a custom OpenAI-compatible endpoint. Switch any time; set a fallback.	A model selected and operated by the vendor; not user-selectable.
Account	No Fud AI account or login required.	Usually requires creating an account.
Where your diary lives	Locally on your device by default. Optional iCloud / Google Drive backup to your own storage. No Fud AI-operated cloud sync of your diary.	Typically stored in the vendor's cloud.
Where photos go for analysis	BYOK: directly from your phone to the provider you chose. Optional iOS hosted mode: through Fud AI's proxy to Gemini.	To the vendor's servers, then to their AI provider.
Ads / analytics SDKs	None.	Varies by app; check its privacy label.
Logging inputs	Up to 10 photos per analysis with a note, barcode (Open Food Facts), voice (6 STT options), text, saved meals, manual entry; Siri Shortcuts and Share Extension on iOS.	Usually photo plus barcode and text; details vary.
Beyond calories	30+ nutrients, weight and body fat, optional water and fasting, workout diary with 877-exercise library, AI Coach, widgets, Apple Watch, optional Apple Health / Health Connect sync.	Varies by app.
Platforms	iPhone (iOS 17.6+) and Android (8.0+), 18 languages.	Varies by app.

Price: free forever vs. subscription

Hosted AI calorie apps pay for every photo you analyze, so they need a subscription to stay in business. Fud AI sidesteps that cost by letting you bring your own key: a free Google Gemini API key takes about a minute to create, OpenRouter's openrouter/free default routes to a free vision model, and Ollama runs open-weight models on your own computer for nothing. There is no paywalled feature tier in the free app — nutrients, Coach, workouts, widgets, and Health sync are all included. Development is supported by an optional iOS Tip Jar and Ko-fi. Read more on the free AI calorie tracker page.

Who controls the AI

With a hosted app, the model is a black box that can change without notice. Fud AI supports 13 providers and current vision presets such as Gemini 3.5 Flash-Lite and 3.6 Flash, GPT-5.4 Mini, Claude Sonnet 5, and Grok 4.3, plus open-weight models through OpenRouter, Together AI, Groq, Hugging Face, Fireworks, DeepInfra, Mistral, Ollama, and custom endpoints. You can pair a paid primary model with a free fallback, add Custom AI Instructions once, and switch providers whenever you like. See the AI food scanner page for how a scan flows.

Where your data lives

Fud AI is local-first. Your food log, photos, weight history, and Coach chats are stored in the app's local container on your phone; API keys live in the iOS Keychain or Android EncryptedSharedPreferences and are never sent to us. In BYOK mode, an AI request goes straight from your device to the provider you configured. Optional iCloud or Google Drive backup uploads to your storage, not ours. Apple Health and Health Connect sync are off until you enable them. The Privacy Policy lists every optional request, and because the app is open source, you can verify that list against the code.

Where a paid hosted app may suit you better

An honest comparison includes the trade-offs:

Setup. Free mode asks you to create an API key and paste it in. It is a one-time minute, but it is a step hosted apps do not have.
Provider terms. In BYOK mode your requests are governed by the provider you chose, and any usage beyond a provider's free tier is billed by that provider, not by Fud AI.
Estimate quality varies by model. You control which model you use, which also means you own that choice.
No free hosted quota. If you prefer zero key management, Fud AI's optional Plus/Pro hosted AI is a paid subscription on iPhone and Android.

If none of that bothers you, you get the same photo-to-log workflow without a subscription, with your data on your device and the code in the open.

Frequently asked questions

Is Fud AI a free alternative to Cal AI?

Yes. Fud AI is a free, open-source AI calorie tracker for iPhone and Android. Instead of charging a subscription to cover AI costs, it uses Bring Your Own Key: you connect a free API key from a provider such as Google Gemini and the app analyzes meals with it. BYOK is free forever, with no ads and no required account.

Do I have to set up an API key to use Fud AI?

For AI photo analysis in free mode, yes — a free Gemini key takes about a minute. Barcode lookup, manual entry, saved meals, and native speech work without any key. On iPhone, an optional Plus/Pro hosted AI plan is available if you would rather not manage a key; it is never required.

Is Fud AI affiliated with Cal AI?

No. Fud AI is an independent open-source project by Apoorv Darshan. Cal AI is a trademark of its respective owner, and references on this page are for comparison only, based on publicly available information.

Where does my food data go with Fud AI compared to a hosted AI calorie app?

Fud AI is local-first: your diary, photos, and history stay on your device, and in BYOK mode each AI request goes directly from your phone to the provider you chose. Hosted AI calorie apps generally route photos and diary data through their own servers and store them there under their privacy policies.

What does Fud AI not do as well as a subscription app?

Free mode asks you to create and paste an API key, and estimate quality depends on the model you pick. There is no free hosted AI quota. If you want zero setup and are happy paying a subscription, a hosted app may feel simpler. AI estimates in any app are approximations; see the Terms of Service.

Try the free alternative

Fud AI is free to install on both platforms. Start with barcodes and manual entry, or paste a free key and scan your next meal.