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Set environment variables

Configure your environment variables to allow Percy builds to run seamlessly

Percy integrates with your tests using both Percy and BrowserStackSDK. To establish this integration, choose the appropriate SDK and refer to the following section accordingly:

BrowserStack SDK
Percy SDK

To seamlessly integrate your visual and functional testing processes for your website, execute your Percy tests on BrowserStack’s Automate. If you’re already an Automate user and wish to explore Percy, you can do so as well. Leveraging BrowserStack SDK for running your tests fulfills all requirements.

Supported parameters

Percy client libraries retrieve additional details from the environment they are running in, including the branch name, commit SHA, GitHub Pull Request number, and more. You can modify certain aspects of Percy’s behavior by configuring these environment variables within your CI environment:

Environment Variable	Description
`PERCY_BRANCH`	The branch in which the build is being executed. Default is the current git branch.
`PERCY_PULL_REQUEST`	The pull request number to link with the build, if any.
`PERCY_PARALLEL_TOTAL`	The total number of parallel builds to expect. \n- In most setups this is automatically discovered and does not need to be set. To know more, read Parallel test suites.
`PERCY_PARALLEL_NONCE`	A unique identifier used to group parallel builds. This can be any string that is shared between parallel runners, such as the CI build number. \n - In most setups this is automatically discovered and does not need to be set. To know more, read Parallel test suites.
`PERCY_PARTIAL_BUILD`	Set to 1 to indicate the build is a partial build, and that it intentionally will be a subset of the snapshots from a full build.
`HTTP_PROXY`	Set http proxy that Percy cli should use in case you need to access internet over a corporate proxy.
`HTTPS_PROXY`	Set https proxy that Percy cli should use in case if you need to access internet over a corporate proxy In most cases setting only `HTTP_PROXY` should suffice, but if you have separate proxies for HTTP and HTTPS feel free to set both. The format for proxy’s is `http[s]://<username>:<password>@<domain.com>:<port>/` [`username` and `password` is optional].
`PERCY_COMMIT`	Set this to the Git commit SHA to ensure that visual tests and snapshots taken by Percy are correctly linked to a specific commit in the version control system.
`PERCY_GZIP`	Set this to `true` to potentially optimize resource size within the 25 MB threshold limit. The default is set to `false`.
`PERCY_DO_NOT_USE_CAPTURED_COOKIES`	Set this to `true` to stop the use of auto-captured cookies. The default is set to `false`.

Environment Variable	Description
`PERCY_TOKEN`	A Percy token is a project-specific, write-only API key.
`PERCY_BRANCH`	The branch in which the build is being executed. Default is the current Git branch.
`PERCY_CLIENT_ERROR_LOGS`	Set this to `false` to prevent the test script from sending error logs to Percy.
`PERCY_TARGET_BRANCH`	The branch for comparison. Default is set to `master`. If the Percy build is associated with a GitHub Pull Request, setting this value will have no effect and the target branch will be automatically determined based on the GitHub PR. For more information, see the base build selection.
`PERCY_TARGET_COMMIT`	The full commit SHA of an existing Percy build to be used as the reference baseline. For more information, see the base build selection.
`PERCY_PULL_REQUEST`	The pull request number to link with the build, if applicable.
`PERCY_PARALLEL_TOTAL`	The total number of expected parallel builds. - In most setups this is automatically discovered and does not need to be set. For more information, see the Parallel test suites.
`PERCY_PARALLEL_NONCE`	A unique identifier used to group parallel builds. This can be any string that is shared between parallel runners, such as the CI build number. - In most setups this is automatically discovered and does not need to be set. For more information, see the Parallel test suites.
`PERCY_PARTIAL_BUILD`	Set to `1` to indicate the build is a partial build, and that it intentionally will be a subset of the snapshots from a full build.
`PERCY_ENABLE`	Set to `0` to prevent Percy from running in your CI environment. This is useful if you want to disable Percy in certain scenarios.
`PERCY_DEBUG`	Set to `true` to debug asset discovery and do not upload snapshots.
`PERCY_LOGLEVEL`	Set this variable to one of the following values: `info`, `silent`, `warn` or `debug`.
`HTTP_PROXY`	Set the HTTP proxy that Percy CLI should use in case you need to access internet over a corporate proxy.
`HTTPS_PROXY`	Set the HTTPS proxy that the Percy CLI should use if you need to access the internet through a corporate proxy. In most cases, setting only `HTTP_PROXY` is sufficient. However, if you have separate proxies for HTTP and HTTPS, you can set both. The format for proxies is `http[s]://<username>:<password>@<domain.com>:<port>/` [`username` and `password` is optional].
`PERCY_PAC_FILE_URL`	Use this variable to specify the path to your PAC config file, this enables proxy functionality based on the specified path. Note: If the `PERCY_PAC_FILE_URL` environment variable is set, it will take precedence over other Percy proxy variables. How to use this variable: - Example of the file path in storage: `pac+file://C:/Users/<username>/.proxy/pac_file.pac` - Example of fetching the file from the web: `pac+http://localhost:8000/app_proxy.pac`.
`PERCY_NETWORK_IDLE_WAIT_TIMEOUT`	Specifies the maximum time the Percy CLI’s resource discovery browser waits for the `networkIdleTimeout` to occur. The default value is 30000ms (30 seconds).
`PERCY_PAGE_LOAD_TIMEOUT`	Specifies the maximum time the Percy CLI’s resource discovery browser waits for the page to load. The default value is 30000ms [ 30 seconds ].
`PERCY_SKIP_UPDATE_CHECK`	Set this to `true` to skip CLI update checks. By default, the CLI queries api.github.com for newer release tags unless this environment variable is set to `false`.
`PERCY_COMMIT`	Set this to the Git commit SHA to ensure that visual tests and snapshots taken by Percy are correctly linked to a specific commit in the version control system.
`PERCY_DO_NOT_CAPTURE_RESPONSIVE_ASSETS`	Set this to `true`, and it will not capture responsive assets like images for that page. The default is set to `false`.
`PERCY_EXIT_WITH_ZERO_ON_ERROR`	Set this variable to `true` to exit with code `0` for any Percy-related errors and generate the error logs. The default value is `false`.
`PERCY_GZIP`	Set this to `true` to potentially optimize resource size within the 25 MB threshold limit. The default is set to `false`.
`PERCY_DO_NOT_USE_CAPTURED_COOKIES`	Set this to `true` to stop the use of auto-captured cookies. The default is set to `false`.
`RESPONSIVE_CAPTURE_SLEEP_TIME`	Set this variable to specify the time in seconds to explicitly wait after each resize if you notice your webpage is not loading properly at certain widths. The default value is `0`. For more information, see Capturing responsive snapshots.
`PERCY_RESPONSIVE_CAPTURE_MIN_HEIGHT`	Set this to override the minimum height for the viewport during capture.
`PERCY_RESPONSIVE_CAPTURE_RELOAD_PAGE`	Set this to `true` to reload the page before capturing each width. The default is set to `false`.
`PERCY_STORYBOOK_DOC_CAPTURE`	Captures visual snapshots of standalone .mdx documentation pages.
`PERCY_STORYBOOK_AUTODOC_CAPTURE`	Captures visual snapshots of Storybook’s auto-generated documentation pages (“Autodocs”).
`PERCY_IGNORE_TIMEOUT_ERROR`	Set this to `true` to prevent build failures when individual snapshots time out with “Snapshot took too long to render” errors.

Components of Feature	Read	Write	Full
Synchronous Comparison Results	No	No	Yes
Percy Screenshot	No	Yes	Yes
Percy Snapshot	No	Yes	Yes
Upload screenshots	No	Yes	Yes
CI Integration	No	Yes	Yes
API Reference - GET	Yes	No	Yes
API Reference - PUT/POST	No	Yes	Yes

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Set environment variables

Supported parameters

Run Percy locally

Run from your CI setup

Supported parameters

PERCY_TOKEN access levels

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