# Device emulation using playwright options flag in synthetics cli

**URL:** <https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899>\
**Category:** Synthetics\
**Created:** [September 12, 2025, 10:01am UTC](https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899 "2025-09-12T10:01:53Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![nikki](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@nikki](https://discuss.elastic.co/u/nikki)\
**Post date:** [September 12, 2025, 10:01am UTC](https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899/1 "2025-09-12T10:01:53Z")

</div>

Hi,

Firstly, apologies if I did not include everything I should have as it’s my first time posting.

Elasticsearch, Kibana, Fleet + Elastic Agent versions are all 8.15.1.  
It is on-prem version of Elasticstack.

My issue is that I need help on how exactly –playwright-options should be used in the synthetics CLI. Currently, I am trying to use the –playwright-options flag in the synthetics cli to dynamically set device emulation. I would like to set the …device option to a mobile or desktop configuration.

Below is my current command that I am running in my terminal (powershell):

```powershell
$deviceName="Galaxy A55";`$device='{"...devices["' + $deviceName + '"]}';npx /synthetics . --playwright-options $device

```

This current command throws an error “SyntaxError: Expected ':' after property name in JSON at position 15 (line 1 column 16)”.

I have also tried this version as my JSON and my tests run but the device doesn’t change to mobile.

```powershell
$deviceName="Galaxy A55"; $device='{ "device":"' + $deviceName + '"}'; npx /synthetics . --playwright-options $device

```

I have looked at the docs, in particular this: [Configure a Synthetics project | Elastic Docs](https://www.elastic.co/docs/solutions/observability/synthetics/configure-projects) but it only shows how to set the device emulation in the config file and not in the CLI.

I would appreciate any help or pointers on what I am doing wrong.  
Thank you.

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<div class="post-metadata">

**Author:** ![nikki](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@nikki](https://discuss.elastic.co/u/nikki)\
**Post date:** [September 16, 2025, 12:30pm UTC](https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899/2 "2025-09-16T12:30:03Z")

</div>

Turns out I needed to specify the entire device descriptor, found in: [https://github.com/microsoft/playwright/blob/main/packages/playwright-core/src/server/deviceDescriptorsSource.json](https://github.com/microsoft/playwright/blob/main/packages/playwright-core/src/server/deviceDescriptorsSource.json)

my json needed to be something like this:

```powershell
$device = '{\"userAgent\":\"Mozilla/5.0 (iPhone; CPU iPhone OS 17_5 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/26.0 Mobile/15E148 Safari/604.1\", \"viewport\":{\"width\":393,\"height\":852}, \"screen\":{\"width\":393,\"height\":659}, \"deviceScaleFactor\":3, \"isMobile\":true, \"hasTouch\":true, \"defaultBrowserType\":\"webkit\"}'

```

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<div class="post-metadata">

**Author:** ![shahzad31](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/shahzad31/32/51637_2.png) [@shahzad31](https://discuss.elastic.co/u/shahzad31)\
**Post date:** [September 16, 2025, 12:44pm UTC](https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899/3 "2025-09-16T12:44:50Z")

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@nikki i think we do export devices constant from the lib, it can be used like this

```auto
import type { SyntheticsConfig } from '@elastic/synthetics';
import { devices } from '@elastic/synthetics';

export default env => {
  const config: SyntheticsConfig = {
    params: {
      url: 'https://elastic.github.io/synthetics-demo/',
    },
    playwrightOptions: {
      ignoreHTTPSErrors: false,
      ...devices['Desktop Chrome'],
    },

```

---

<div class="post-metadata">

**Author:** ![nikki](https://avatars.discourse-cdn.com/v4/letter/n/6a8cbe/32.png) [@nikki](https://discuss.elastic.co/u/nikki)\
**Post date:** [September 16, 2025, 2:11pm UTC](https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899/4 "2025-09-16T14:11:29Z")

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Hi @shahzad31,

I did try that in the beginning, but in my case I want to dynamically push one test with different configurations without creating multiple config files . So like this I have one test and one config file but I can push different monitors that test against different devices (i.e. mobile and desktop).

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<div class="post-metadata">

**Author:** ![shahzad31](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/shahzad31/32/51637_2.png) [@shahzad31](https://discuss.elastic.co/u/shahzad31)\
**Post date:** [September 16, 2025, 2:23pm UTC](https://discuss.elastic.co/t/device-emulation-using-playwright-options-flag-in-synthetics-cli/381899/5 "2025-09-16T14:23:19Z")

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well you can specify the same playwrightOptions within a journey as well, via monitor.use hook