Fast AI
AI models from OpenAI, Google, Anthropic, xAI and DeepSeek in one chat on your iPhone. Pick one, switch whenever you like.
Subscription: $5.99 a week, $9.99 a month or $69.99 a year (US App Store).
Download on the App StoreWhat it does
- Five model families, one appModels from OpenAI, Google (Gemini), Anthropic (Claude), xAI (Grok) and DeepSeek. One subscription instead of one per company.
- Switch in the middle of a chatAsk the same question to another model, or move to a faster one for quick tasks and a stronger one for hard ones.
- Web searchTurn it on when you need current information: news, prices, opening hours.
- Read aloudHave any answer spoken with the voices on your iPhone.
- In your languageThe interface is in English, Spanish, Brazilian Portuguese, Japanese and Korean. The models answer in almost any language.
What it does not do
Fast AI is chat only. It does not generate images or video, does not read PDFs or other files, and has no voice input. There is no free tier: chatting needs a subscription. Each subscription has a daily usage limit that resets at midnight UTC, and heavier models use it up faster. If you want chat and images in one app, see Brainy; for AI video, Dora.
We compared Fast AI with the other apps that offer several AI models, including where they beat us, in Best AI chat apps with multiple models for iPhone.
Questions
Which AI models does Fast AI use?
Models from OpenAI, Google (Gemini), Anthropic (Claude), xAI (Grok) and DeepSeek, reached through OpenRouter. We move to newer versions as the companies release them, so we list the companies rather than version numbers here; the app shows the current names.
Is Fast AI free?
It is free to download, but chatting needs a subscription: $5.99 a week, $9.99 a month or $69.99 a year on the US App Store. Local prices vary.
Is it unlimited?
No. Each subscription has a daily usage limit that resets at midnight UTC, and web search can be used a few times a day. Heavier models use up the daily limit faster.
Is Fast AI made by OpenAI?
No. Fast AI is made by Saga Labs, an independent studio. It is not affiliated with OpenAI, Google, Anthropic, xAI or DeepSeek; it uses their models through their APIs.
Can it make images or read PDFs?
No. Fast AI is chat only: no image generation, no file or PDF upload and no voice input. For chat plus images, our other app Brainy does both.
Where do my messages go?
To our server, which forwards them to the model you picked through OpenRouter and returns the answer. Your chats are kept on your iPhone. We count tokens per subscription to enforce the daily limit.
Fast AI is made by Saga Labs, an independent app studio.