Attackers drove a Vercel docs AI chat endpoint to 1,300 req/min in an attempted inference theft

On April 12, 2026, traffic to Vercel's own docs AI chat endpoint spiked to roughly ten times normal volume on Anthropic's Claude Haiku 4.5, peaking at 1,300 requests per minute - a run rate Vercel says would have translated to over $10,000 per day of inference cost. The attack came through residential proxies that hid real client IPs, so per-IP rate limits had nothing to act on across hundreds of thousands of bot requests over two days. Vercel's per-request BotID deep-analysis gate blocked more than ten thousand bot requests in the first minutes of the spike; no realized loss figure was published.

What this means for youAttackers can run up large bills on a company's public AI chatbot by flooding it with bot traffic. If your business runs a public AI assistant, ask your provider about per-request bot filtering and spending caps.