---
title: cf.timings.worker_msec
description: The time spent executing a Cloudflare Worker in milliseconds.
image: https://developers.cloudflare.com/core-services-preview.png
---

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#  cf.timings.worker\_msec 

`cf.timings.worker_msec` ` Integer ` 

The time spent executing a Cloudflare Worker in milliseconds.

This field provides the wall-clock time that a Cloudflare Worker spent handling the request, measured in milliseconds.

Use this field to identify slow Worker executions, set up alerts for performance regressions, or add Worker execution time as a request header using Transform Rules for downstream observability.

If the request did not invoke a Worker, the value of this field will be `0`.

Example value:

```
12
```

Example usage:

```
# Matches requests where the Worker execution time exceeded 500 millisecondscf.timings.worker_msec > 500
```

Categories: 
* Request

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