What a rate limit is
A rate limit is a floor on the time between two messages, usually a few seconds. A cap is a ceiling on the number of messages in a period, usually a day. A rate limit protects shared hardware from bursts and clears the moment you wait; a cap protects a price and clears on a clock.
Both stop you from sending the next message, so people file them under the same word. They are different mechanisms with different owners inside a company, and telling them apart changes what you should do when you meet one.
On this page
A rate limit measures time between requests
The server records when your last message arrived. If the next message arrives sooner than the allowed gap, it is refused and you are asked to wait. The gap is small, often 1 to 5 seconds, and nothing accumulates. Wait the gap and you are back where you were, with no balance spent and nothing to reset.
A cap counts requests and keeps the count
A cap has memory. Every message subtracts from a number that only refills when the period turns over. Sending slowly does not help, because the count does not care about time between messages. This is the mechanism people mean when they say an assistant ran out.
Why a rate limit is a fair thing to have
One person sending 50 requests per second makes the service slower for everyone else on the same hardware. A few seconds between messages costs a human reader nothing, because reading the previous answer takes longer than the gap. It also stops automated abuse without touching normal use.
How to tell which one stopped you
Read the message and look for a clock. A rate limit says wait, names a small number of seconds, and lets you through immediately after. A cap names a time of day, a date, or a plan. If the wording offers you an upgrade, the mechanism is a cap, whatever the page calls it.
Fair questions
Can a service have both?
Most do. A rate limit protects the hardware and a cap protects the pricing, and they run independently of each other.
Does a rate limit slow the answer itself?
No. It decides when your next message is accepted. Once a message is accepted, the answer streams at the speed the model produces it.
Is a rate limit ever used as a hidden cap?
It can be, and the sign is a gap that grows the longer you talk. A fixed gap of a few seconds is a rate limit; a gap that stretches to minutes is a cap with a friendlier name.
Try a chat where the only wait is a few seconds between messages.
Open unrestricted chat