Website visits made by automated programs instead of people.
It is like robot shoppers grabbing every concert ticket. They never go to the show, but your cart still says sold out.
You meet it in crawlers and API calls. When it runs wild, it eats bandwidth and raises the site's bill.
API
Many bots skip web pages and hit the API again and again.
Agent
Agents can run tasks in bulk, so they can create bot traffic.
CAPTCHA
CAPTCHA helps block bot visits and let real people through.
Usage cap
When bots flood a service, a usage cap helps slow them down.