# RateLimitAlgorithm

A model the API reference uses in a request or a response. The operation pages link every field typed as this model here.

The algorithm used to enforce a rate limit.

## Values

| Value | Description |
| --- | --- |
| `FixedWindow` | Fixed (tumbling) window: the counter resets when the window rolls over. The window identifier is derived from the current UTC instant, so every process agrees on the boundary without coordination. |
| `SlidingWindow` | Sliding window: tracks individual request timestamps over a rolling span using a sorted set. More precise than a fixed window at the cost of more Redis memory. |
| `TokenBucket` | Token bucket: permits replenish at a steady rate and short bursts are allowed up to the bucket capacity. |
| `Concurrency` | Concurrency limiter: bounds the number of concurrent in-flight requests. The slot is held for the duration of the downstream request and released afterwards. |

## See also

- [All documentation](https://devportal.demo.winkpg.io/llms.txt): the machine-readable index of every public page on this site.