# PHP metrics

Source: https://docs.fortrabbit.com/platform/metrics/php
Published: 2026-10-24
Updated: 2026-10-24
Reviewed: 2026-10-24

> How fortrabbit measures PHP response time, PHP requests, PHP memory, the OPcache fill level and OOM kills of an environment, and how to read each chart.


## PHP response time

The load balancer times every PHP request. Per sample it keeps three things: how many requests fell into each duration range, the sum of all durations, and the slowest request. Every value of the chart is computed from these:

- max: the slowest single request of the hour or day. It is exact. One stuck request sets it, so it often runs out of the chart.
- avg, med, 99ile: one of the three, picked under "Measure", see [average, median and 99ile](/platform/metrics/values#average-median-and-99ile).

The figures in the box are computed from all requests of the time frame at once, not from the bars. The fastest request is not recorded. The lines mark Fast, Good and Slow. See [PHP processes](/dev/performance/php-processes#php-processes-php-requests-php-response-time).

The response time shows how long PHP took. The [logs](/platform/settings/logs) name the slow URLs, and an [APM tool](/integrations/apm/intro) traces a slow request through the code, down to the query or function.

## PHP requests

Requests that run PHP. A sample holds the requests answered since the sample before, a bar is the sum of its samples. Static files are counted separately, under [static requests](/platform/metrics/storage-traffic#static-requests). See [PHP processes vs page views](/dev/performance/php-processes#php-processes-vs-page-views).

## PHP memory

The memory the PHP containers use. A sample holds the highest memory since the sample before, so it catches short spikes. A bar shows two values:

- max: the highest sample of the hour or day. Compare it with the memory of the plan, drawn as a line.
- typical peak: the median sample. Half of the samples were lower, half higher.

A typical peak far below the max means the memory stayed low most of the time and spiked now and then. See [out of memory](/dev/performance/out-of-memory#php).

## PHP OPcache

How full the OPcache is, the memory that holds compiled PHP code. A sample holds the highest fill level since the sample before, a bar the highest sample of the hour or day. Keep it below the Nearly full line. See [keep OPcache below full](/dev/performance/backend#keep-opcache-below-full).

## OOM kills

PHP processes the system ended because the environment needed more memory than the plan has. A bar is the number of kills in that hour or day. See [out of memory](/dev/performance/out-of-memory#php).

## Labels and lines

The values each metric shows in one bar, for the time frame, and on the summary page, and the lines drawn across the chart:



---

- [PHP processes](/dev/performance/php-processes)
- [Out of memory](/dev/performance/out-of-memory)
- [Metric values](/platform/metrics/values)