How Websites Get Unexpected Traffic Spikes

A sudden jump in traffic looks exciting in your analytics dashboard. But the source matters more than the number. A genuine viral moment behaves very differently from a bot flood, and treating them the same way can leave you either over-provisioned or under attack.

Common causes of unexpected spikes

• Viral content: a post, page, or tool gets shared widely. Traffic arrives in a short window, mostly from referral or direct.
• Scraper bursts: a scraper indexes your entire site in minutes. Hits are evenly distributed across pages, with no session depth.
• Bot floods: coordinated bots hammer a single endpoint, often login or checkout. Requests per second is high; conversion is zero.
• Crawler misconfiguration: a search engine bot ignores crawl-delay settings and floods your server with parallel requests.
• Linked by a large publication: traffic arrives from a single referrer domain and drops sharply within 24-48 hours.

How to tell them apart

Look at session depth and bounce behavior. Real visitors navigate. Bots don't. Also check the user-agent distribution and TLS fingerprints. A spike made up of hundreds of unique IPs all sharing the same JA3 fingerprint is a bot burst, not a viral moment.

Karbon surfaces this at the edge in real time, so you see the breakdown before it affects your origin.