Simultaneous requests.
WHAT IT MEASURES
How many requests your account is processing at the same moment.
Not requests per hour. Requests at once.
WHY IT MATTERS
It is the limit most small sites hit first.
THE SYMPTOM
A 508 error, or requests failing while the site works moments later.
Intermittent and confusing.
WHAT CAUSES IT
Slow pages, since a slow page occupies a slot longer Bot traffic arriving in bursts A traffic spike Long-running requests
THE SLOW PAGE CONNECTION
If pages take five seconds, far fewer simultaneous visitors exhaust the limit than if pages take half a second.
Speed and this limit are directly connected.
WHAT TO DO
Enable caching, which makes pages fast and removes PHP entirely for cached responses Fix slow pages Control bot traffic
WHAT NOT TO DO
Assume you need a larger plan because of a brief spike.
Fix the slowness first.