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Install Custom Certificates on the VM Through Pre-run-executables

Pre-run-executables allow you to run your custom scripts before the Selenium test is started. We can use this feature to install user custom certificates that are mandatory for test cases to execute successfully.

To use certificates for Selenium tests, we require 3 things:

  • Certificate file.
  • The script that installs the certificate in our Virtual Machine (VM).
  • The script that deletes the certificate in our VM.


Upload your certificate file, installation, and uninstallation script using the below instructions.

  1. Upload your certificate using the below command.
curl --location --request POST '<>'
  1. For installing certificate on macOS, use the following command.
sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /Users/ltuser/Downloads/{CERTIFICATE-FILE-NAME}
  1. For installing certificate on Windows, use the below command.
Import-Certificate -FilePath "C:\Users\ltuser\Downloads\{NAME-OF-THE-CERTIFICATE}" -CertStoreLocation 'Cert:\LocalMachine\Root' -Verbose
  1. Use the following cURL request to upload pre and post run file altogether.
curl --request POST \
--url <> \
--header 'Authorization: Basic {TOKEN}' \
--header 'Content-Type: multipart/form-data' \
--header 'cache-control: no-cache,no-cache,no-cache' \
--header 'content-type: multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW' \
--form 'name={NAME-OF-YOUR-PRERUN}'
  1. Now run the below capabilities to use the certificate, pre and post run files in a test.
"lambda:userFiles": ["certificate.p12"],
"prerun": {
"accessKey": "****",
"background": False,
"filePath": "xyz/pre/install_certificate.ps1",
"postAction": {
"filePath": "xyz/post/delete_certificate.ps1",
"url": "<>"
"url": "<>",
"user": "****"


  1. After uploading your pre-run script, reach out to us either via chat support or email to get the scripts approved.

  2. Once your script is approved, pass the prerun key in capability as

"prerun": {

Note: Replace {NAME-OF-YOUR-PRERUN} as provided in Step 1 and {NAME-OF-YOUR-CERTIFICATE-INSTALLATION-FILE-NAME} with the name of the certificate installation script that you uploaded in Step 1.

Leverage the use of APIs to Pre-run Tests

Here are the prerun APIs:

  • GET/files: Fetch all pre run files uploaded by the user.
  • POST/files: Upload pre run executable file to our lambda storage.
  • DELETE/files/delete: Delete pre run from our lambda storage.
  • POST/files/validate: Check if the file is approved by LambdaTest.
  • PUT/files/download: Download pre run executable file.

Note: To know more about our APIs, check out our API Documentation.

Sample Certificate Installation and Uninstallation File (macOS)

  • In replace {CERTIFICATE-FILE-NAME} with the certificate file name.
  • In replace {CERTIFICATE-NAME} with the certificate name (You can use the Keychain Access to find the certificate name.)

Following are the contents of the sample file:

For Installing:

sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /Users/ltuser/Downloads/{CERTIFICATE-FILE-NAME}

For Deleting:

sudo security delete-certificate -c "Local Certificate"

Sample Certificate Installation and Uninstallation File (Windows)

  • In install_certificate.ps1 replace {CERTIFICATE-FILE-NAME} with the certificate file name.
  • In delete_certificate.ps1 replace {CERTIFICATE-NAME} with the certificate name.

Following are the contents of the sample file:

For Installing:

Import-Certificate -FilePath "C:\Users\ltuser\Downloads\{NAME-OF-THE-CERTIFICATE}" -CertStoreLocation 'Cert:\LocalMachine\Root' -Verbose

For Deleting:

Get-ChildItem Cert:\CurrentUser\Root\{THUMBPRINT-OF-THE-CERTIFICATE} | Remove-Item

Got any questions?
Please reach out at our 24x7 Chat Support or you could also mail us at