> ## Documentation Index
> Fetch the complete documentation index at: https://docs.limitem.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Sliding Window

> A moving window. No cliff.

Every allowed request stores a timestamp. A request is allowed if fewer than `limit` timestamps fall inside the last `duration` seconds.

```text theme={null}
limit = 3, duration = 10s

t=0   allowed   [req1]
t=3   allowed   [req1, req2]
t=6   allowed   [req1, req2, req3]
t=8   blocked   window still full
t=11  allowed   req1 aged out
```

## When to use it

When "100 per hour" must mean 100 in any 60-minute stretch — not 100 at 10:59 and 100 at 11:00.

## Notes

There's a ceiling: **100,000** requests in a single window. Above that, use token bucket or leaky bucket.

`reset_time` is when the oldest request in the window expires — the moment a slot frees up.