> ## 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` | *float* | :heavy\_check\_mark: | Median (50th percentile) | 25.5    |
| `p75` | *float* | :heavy\_check\_mark: | 75th percentile          | 35.2    |
| `p90` | *float* | :heavy\_check\_mark: | 90th percentile          | 48.7    |
| `p99` | *float* | :heavy\_check\_mark: | 99th percentile          | 85.3    |