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

# PercentileStats

Latency percentiles in milliseconds over the last 30 minutes. Latency measures time to first token. Only visible when authenticated with an API key or cookie; returns null for unauthenticated requests.

## Fields

| Field | Type | Required | Description | Example |
| - | - | - | - | - |
| `P50` | `float64` | :heavy\_check\_mark: | Median (50th percentile) | 25.5 |
| `P75` | `float64` | :heavy\_check\_mark: | 75th percentile | 35.2 |
| `P90` | `float64` | :heavy\_check\_mark: | 90th percentile | 48.7 |
| `P99` | `float64` | :heavy\_check\_mark: | 99th percentile | 85.3 |