The hosting itself can genuinely be free. The real cost is almost always the AI API you’re calling. A lot of people building their first AI app assume the expensive part is keeping the website online. In practice, static hosting for the front end is often free, and the ongoing cost comes from every request your app sends to an AI model.

Where the real cost comes from

AI APIs from OpenAI, Anthropic, and Google are billed per token, a unit of text roughly equivalent to a few characters, counting both what you send the model and what it sends back. A single simple chatbot response might cost a fraction of a cent, but that adds up fast once real users are sending requests continuously, especially if your app doesn’t limit how much text a single request can generate.

The costs people forget to plan for

Beyond the API bill itself, a few costs catch first-time builders off guard: a database for storing user data or conversation history, which most free hosting tiers don’t include; a backend function to keep your API key secure server-side, which may have its own usage-based pricing once you exceed a free tier; and rate limiting infrastructure to stop a single user, or a bot, from running up your AI bill by sending unlimited requests.

How to actually estimate your cost before launch

Look up your chosen AI provider’s per-token pricing, then estimate a realistic average request size and how many requests you expect per active user per day. Multiply that out across your expected user count, and add meaningful margin, since usage is rarely as predictable as a spreadsheet suggests. Setting a hard spending cap or usage alert with your API provider before launch is a simple, real safeguard against an unexpectedly large bill.

Frequently asked questions

Is hosting an AI app expensive?

The front-end hosting itself can be free on platforms like Netlify or Cloudflare Pages. The AI API calls are where real, ongoing costs come from.

How are AI API costs calculated?

Per token, a unit of text covering both the request sent to the model and the response it generates, with pricing varying by provider and model.

How do I avoid a surprise AI bill?

Set a hard spending cap or usage alert with your AI provider before launch, and add rate limiting so a single user can’t send unlimited requests.

For more on getting an AI project actually live, see How to Deploy an AI App for Free.