FuelFit — AI Provider Setup Guide
How to get an API key and enable AI food photo analysis
- No backend server — all your data stays encrypted on your device only
- Direct API calls — AI calls go from your device straight to the provider you chose
- Explicit opt-in — you choose to enable AI during onboarding; you can skip it entirely
- One toggle for minimizing data exposure — the AI Diet Coach can be turned off in Settings. With it off, your provider is contacted only when you actively take a food photo.
- Honest AI label — when coaching falls back to a built-in template, the "AI" badge disappears so you always know what's actually generated
- Export/Import — your data is portable via Settings → Export/Import
How Much Does It Cost?
FuelFit uses AI to analyze your food photos. You bring your own API key (BYOK) — there is no subscription fee from FuelFit itself. The cost depends entirely on which provider you choose and how often you log meals.
Estimated Annual Cost (Active User)
Based on ~6 photos/day + 12 coach calls/day, 365 days/year
| Provider | Default Model | Estimated Annual Cost | Notes |
|---|---|---|---|
| Qwen (Alibaba) | qwen3-vl-flash |
~$0.69 / year | Cheapest · Default Strong food recognition; ideal for users in China |
| OpenAI | gpt-4o-mini |
~$1.45 / year | Most reliable Widely supported, predictable behavior |
| Mistral | mistral-small-latest |
~$1.60 / year | EU-based Open-weights provider, good privacy stance |
| Custom | Your choice | Varies | Any OpenAI-compatible endpoint — OpenRouter, Claude, self-hosted, etc. |
qwen3-vl-flash to qwen3-vl-plus for higher accuracy, or to gpt-4o on OpenAI, before you verify.
- Pricing Control: All API rates and cost estimates are provided for reference only. AI providers control their own pricing and can change rates at any time. FuelFit does not charge subscription fees, does not process billing, and has no control over API charges.
- Billing Limits: We strongly recommend setting strict hard billing limits (usage caps) on your AI provider's developer dashboard to prevent unexpected charges.
- Medical Disclaimer: FuelFit and its AI coach are for informational and educational purposes only. They do not constitute medical advice. Always consult a qualified healthcare professional before making significant changes to your diet or fitness routine.
Option 1: Qwen / Alibaba Cloud (Default — Cheapest)
Qwen (DashScope) — qwen3-vl-flash
Cheapest · Default
Qwen is FuelFit's default provider. The qwen3-vl-flash model is the cheapest dedicated vision model available and handles food photos especially well, including Chinese cuisine. New Alibaba Cloud accounts get free credits.
Step-by-Step Setup
Go to account.alibabacloud.com/register (international) or account.aliyun.com (China) and sign up.
Go to bailian.console.aliyun.com and activate the Model Studio service. New accounts get free credits (1 million tokens) — enough for months of normal use.
In the Model Studio console → API Key Management → click "Create API Key" → copy the key (starts with
sk-).
Open FuelFit → Settings → AI Services → make sure Qwen is selected (it's the default). Base URL and model arrive pre-filled — bump
qwen3-vl-flash to qwen3-vl-plus if you want higher accuracy. Paste your key and tap Verify Connection.
qwen3-vl-flash model is specifically designed for image understanding and is the cheapest vision model available.
Option 2: OpenAI (Most Reliable)
OpenAI — gpt-4o-mini
Most reliable
OpenAI offers strong reliability and broad ecosystem support. Slightly more expensive than Qwen but extremely predictable behavior — a solid default if you're not in China.
Step-by-Step Setup
Go to platform.openai.com/signup and sign up with your email or Google/Microsoft account.
Navigate to Settings → Billing and add a credit card. You can start with as little as $5.
Go to API Keys → click "Create new secret key" → give it a name (e.g., "FuelFit") → click "Create key".
Copy the key immediately (it starts with
sk-). You won't be able to see it again. Store it somewhere safe.
Open FuelFit → Settings → AI Services → select OpenAI. Base URL
https://api.openai.com/v1 and model gpt-4o-mini are pre-filled. Paste your sk-... key, then tap Verify Connection.
Option 3: Mistral (EU-based)
Mistral — mistral-small-latest
EU-based
Mistral is a European AI company with open-weights models. Choose this if you want EU-jurisdiction processing or simply prefer Mistral's stack.
Step-by-Step Setup
Go to console.mistral.ai and sign up.
Navigate to Billing and add a credit card. Mistral offers a free tier with limited usage.
Go to API Keys → click "Create new key" → copy it immediately.
Open FuelFit → Settings → AI Services → select Mistral. Base URL
https://api.mistral.ai/v1 and model mistral-small-latest are pre-filled. Paste your key and tap Verify Connection.
Option 4: Custom (Any OpenAI-Compatible Endpoint)
Custom Provider
Power userIf you want to use a provider that isn't built in — Anthropic Claude, Google Gemini, a self-hosted vLLM server, OpenRouter as a multi-provider gateway, or any other OpenAI-compatible API — pick Custom and enter the endpoint yourself.
Step-by-Step Setup
For example: OpenRouter, Google AI Studio, or your self-hosted server.
Most providers document this. Examples: OpenRouter is
https://openrouter.ai/api/v1; Google's OpenAI-compatible endpoint is https://generativelanguage.googleapis.com/v1beta/openai.
FuelFit needs a multimodal model that accepts images. Examples on OpenRouter:
anthropic/claude-3.5-sonnet, google/gemini-2.0-flash, openai/gpt-4o-mini.
Open FuelFit → Settings → AI Services → select Custom → fill in Name, Base URL, Model, and API Key → tap Verify Connection.
AI Coach Toggle
FuelFit's two AI features have very different data-flow profiles, and only one of them needs a toggle:
- Photo analysis is user-initiated. Nothing is sent to your provider until you tap the camera button. Don't take a photo, no API call happens. There's nothing to toggle off.
- The AI Diet Coach runs automatically. When you open the Insights tab or the Home coach card refreshes, FuelFit sends your daily nutrition summary to your provider to generate a coaching message. That's exactly the kind of background call some users don't want — even to a provider they've chosen — for privacy reasons. So this one gets a toggle.
Turning the AI Diet Coach off keeps photo analysis fully working but stops every other unprompted API call. The Insights coach card silently switches to built-in template tips that are computed entirely on your device.
What Each Feature Does
| Feature | What It Does | When It Calls Your Provider | How to Stop |
|---|---|---|---|
| Food Photo Analysis | Identifies food items and estimates nutrition from photos you take | Only when you tap the camera button | Don't take photos. (Or clear your API key in Settings.) |
| AI Diet Coach | Generates coaching messages and daily summaries from your logged data | Automatically — when you open Insights, when the Home coach card refreshes | Toggle off Settings → AI Services → AI Diet Coach |
Data Transparency
- Food photo analysis: the photo plus a short prompt are sent directly to the AI provider you chose. Nothing else.
- AI Diet Coach (toggle ON): only your daily nutrition summary numbers are sent — calories, protein, carbs, fat, fiber, sugar, sodium, water, meal count. No photos, no profile details, no historical data beyond today.
- Template coaching (toggle OFF or AI failure): messages are computed entirely on-device from your logged data. Nothing leaves your phone.
The "AI" Badge — Honest Attribution
Frequently Asked Questions
Is my API key safe?
Yes. Your AI provider API keys are stored only on your device using the platform’s built-in secure storage — iOS Keychain on Apple devices and Android Keystore-backed encrypted storage on Android (via capacitor-secure-storage-plugin). They are never sent or shared with third parties, or stored in plain text in the app’s local database (IndexedDB or localStorage). Keys are transmitted directly from your device to your chosen AI provider over HTTPS only when you use food photo analysis or AI coach. We never see or collect your data.
What about switching devices?
FuelFit includes a built-in Export/Import function in Settings. Export your data as a file, then import it on your new device. Your meals, settings, and (encrypted) API keys transfer in one step.
Can I use AI for photos only, not coaching?
Yes. Open Settings → AI Services, expand the section, and flip the AI Diet Coach toggle off. This disables AI-generated coaching messages while keeping AI food photo analysis active. The Insights coach card will then show built-in template tips instead, and the "AI" badge will disappear.
Can I use multiple providers?
FuelFit uses one primary provider at a time, but you can configure multiple Custom providers and switch between them in Settings. The three built-in providers (Qwen, OpenAI, Mistral) each remember their own configuration too, so swapping among them is just a tap.
What if I run out of credits?
The app will show an error when you try to analyze a photo or when the AI Diet Coach tries to generate a message. If the coach call fails, the Insights card silently falls back to a template tip (no error toast — and the "AI" badge disappears so you know it's a template). Add credits to your provider account and the next AI call will work again. Your meal history is always saved locally.
Do I need an API key to use FuelFit?
No. FuelFit works without AI for manual meal logging. You only need an API key if you want photo analysis or AI-generated coaching. With no key configured, all coaching uses built-in templates.
Which provider should I choose?
- Default: Qwen
qwen3-vl-flash— cheapest, strong food recognition, free credits for new accounts - Most reliable: OpenAI
gpt-4o-mini— predictable behavior, broad ecosystem support - EU-based: Mistral
mistral-small-latest - Anything else (Claude, Gemini, self-hosted): use the Custom option, ideally via OpenRouter