Your Bolt.new app is serving its anthropic api key to every visitor

Why Bolt does this

Bolt scaffolds Vite projects inside a WebContainer, where everything runs in the browser by definition. Code that works in the preview keeps the key client-side when it is deployed, because nothing in the generated project ever moved it to a server.

Confirm it first

Before rotating anything, check whether the key is actually being served. Paste your deployed URL — KeyDrift downloads the same JavaScript a visitor gets and tells you what is in it.

Rotate the key

Do this before changing any code. The key has been served to browsers, cached by CDNs and very likely scraped already — removing it from the source does not un-publish it.

1. 1Revoke the key in the Anthropic console.
2. 2Review usage for the billing period.
3. 3Put the API call behind a server route with your own rate limiting.

Move the call to a server

The replacement key must not follow the old one into the bundle, which means the code that uses it cannot live in the browser. Any variable named VITE_… is inlined at build time by design — the prefix is the mechanism, not a mistake.

// src/components/Chat.tsx
// Vite substitutes the literal value here at build time.
const key = import.meta.env.VITE_ANTHROPIC_API_KEY;
const result = await new Anthropic({ apiKey: key }).messages.create(body);

// supabase/functions/chat/index.ts  — runs on a serverless function on your deploy target
Deno.serve(async (request) => {
  const key = Deno.env.get('ANTHROPIC_API_KEY')!; // never sent to the browser
  const result = await new Anthropic({ apiKey: key }).messages.create(body);
  return Response.json(result);
});

// src/components/Chat.tsx
const result = await fetch('/functions/v1/chat', { method: 'POST' }).then((r) => r.json());

How KeyDrift detects it

Matches the `sk-ant-api` and `sk-ant-admin` prefixes with their version segment.