The EyesLibrary configuration file

The Robot Eyes configuration file allows you to control various aspects of Eyes testing. The file is in YAML format.

The configuration file content

You can check the latest configuration file by the link. If you have installed EyesLibrary you could initialize the config file with command: python -m EyesLibrary init-config

The applitools.yaml has several top sections:

The shared settings provide defaults for all run types. The other sections are for specific types of run and define their own configuration values. By default, they inherit the shared settings, but they can override any configuration if necessary.

Shared section

The following fields can appear top-level of applitools.yaml conf. Unless noted otherwise, you may also set these values under the other top-level fields (web, mobile_native and selenium_ufg) to define the value when working in that specific mode:



Use this example to define the URL of your Eyes server. If you have an on-prem server or private cloud, you must specify this. If you use the public Eyes server (, then setting this key is optional since this is the default value. If you set the environment variable APPLITOOLS_SERVER_URL to the server URL, then Eyes uses that value as the default.


api_key: YOUR_API_KEY

You must set this value to your Eyes API key. See How to obtain your API key for details.


app_name: my app name

Set the value of the application name property. The application name is one of the five properties that define the baseline. The application name provides the scope to the test name, and tests can be grouped and managed on a per-application basis. See The Apps & tests page for details.


viewport_size:width: 1920height: 1080

Set the viewport size to be used by the browser for the test. The viewport size sets the browser window size, and it is also one of the five values that defines the baseline – the set of images against which this test is checked. See Working with baselines for more details.


   batch_sequence_name: YOUR_BATCH_SEQUENCE_NAME
   - name: BatchPropery 1
     value: some value 1
   - name: BatchPropery 2
     value: some value 2

Set the name of the batch. In the Test manager, all of the results of tests that were executed as a single batch are displayed together and can be managed and operated on as a group. See How to organize your tests with batches for more details.


branch_name: YOUR_BRANCH_NAME

Set the branch to be used as the baseline of the run. The use of a branch in Eyes corresponds to the use of a branch in the source code version control repository. The branch stores one or more baselines. Typically, every version of your software that runs on a source control branch has a corresponding Eyes branch that stores the Eyes baselines that represent the expected results of tests running on that software branch.

If the branch exists, and a matching baseline exists in the branch, then it is used as the basis for comparing the checkpoint images. If the branch does not exist yet and a parent branch, defined by the parent_branch_name value, exists and has a matching baseline, then that baseline is used. Otherwise, the default branch is used. The branch named by the branch_name value is actually created when you view the tests results of a run on this branch, make some changes (i.e. accept a new, changed, or deleted step), and do a save operation.


parent_branch_name: YOUR_PARENT_BRANCH_NAME

Set the parent branch from which newly created branches get their initial baseline. See the explanation of the branch_name for more details.


baseline_branch_name: YOUR_BASELINE_BRANCH_NAME

Set the name of the branch that the baseline reference is taken from and to which new and accepted steps are saved to.The baseline must exist. See Copying baselines between branches to discover how to create such a branch from existing baselines in existing branches. Do not use this option if you are using the branch_name option.


baseline_env_name: YOUR_BASELINE_ENV_NAME

Set this value to specify the name of the environment used to determine the baseline.

Eyes stores a set of mappings from an environment name to an environment E, where E is defined as a triplet <OS, Browser, ViewportSize>. You can specify that Eyes uses the baseline defined by the environment name instead of the test environment by assigning this value to the name of the environment.


save_diffs: true

Set this value to true to specify that steps that have mismatches should be automatically saved to the baseline.

In the usual workflow, if Eyes finds mismatches, you use the Test Manager to view the mismatches, accept or reject the steps with mismatches, and then update the baseline with the images captured in the accepted steps. This method allows you to instruct Eyes so that where steps have mismatches, or where there are new or missing steps, the corresponding steps in the baseline should be updated with the images captured in the current run of the test.

Setting this value to true, completely overwrites your baseline. It is usually preferable to see the results in the Test Manager and, if necessary, to accept all differences there. If you do use this method in a particular circumstance, remember to disable this setting for every day use.


match_timeout: 600

Set this value to specify the maximum amount of time Eyes should try to perform a match on the fully captured image.

Since a browser can take time to render a page (because it is complex, or because of slow network speeds), if Eyes detects mismatches, it initially assumes that the mismatch is because the render has not completed yet, and it retries the match after a short wait. You can set this value to determine how much time Eyes spends retrying the matching before declaring a mismatch.


   url: ""
   host: myhostid
   port: 7200
   username: my name
   password: this is my secret password

If you run tests behind a firewall that can’t access the Eyes server directly, then you can define a proxy server, and the commands are sent to the Eyes server via the proxy server. You must specify the URL. You only need the host, port, username, and password if they are required by the proxy server.


save_new_tests: false

Set this value to false to specify that ‘new’ tests should not be automatically saved to the baseline by default. This option is enabled by default (i.e. new tests are saved automatically to the baseline), so use this method to disable the default behavior.



Set a list of user-defined properties, each of which is a key/value pair. These properties are defined as properties of the test as opposed to batch properties.

You can view these properties and use them to filter and group tests and steps in the Test manager.

Web settings

Desktop and mobile browsers with Selenium and Appium.


web:force_full_page_screenshot: true

By default, Eyes only captures the image visible in the browser viewport. If you set this value to true, Eyes captures and checks all of the content on the web page (anything accessible by scrolling the top-level element).


web:wait_before_screenshots: 100

Set this value to specify the amount of time (in milliseconds) that Eyes should wait before capturing a screenshot. This can be used if the image takes time to stabilize if, for example, there is an animation, meaning there is no synchronous way to wait for the image to be stable before calling the checkpoint command.

When a large image is captured with multiple sub-images using scrolling and stitching, Eyes waits the amount of time specified by this method before capturing each sub-image. Setting a value less than or equal to zero sets the default wait time.


web:stitch_mode: CSS# Scroll | CSS

When you set force_full_page_screenshot to true, Eyes captures the entire page, element, or frame by capturing multiple images across the page and stitching them together. The stitch mode defines the method for doing this. The default value is Scroll, but the recommended value is CSS.


web:hide_scrollbars: true

Set this value to true so that Eyes hides the scrollbars before capturing screenshots, or set it to false to disable hiding the scrollbars. Hiding the scrollbars is recommended to avoid false mismatches caused by differences in the scrollbar position each time the checkpoint is captured and checked.


web:hide_caret: true

Set this value to true so that Eyes hides the cursor before the screenshot is captured. This is recommended to avoid mismatch artifacts caused by a blinking cursor.

Mobile native settings

Mobile apps with Appium.


mobile_native:is_simulator: true

Set this value to true when the device under test is a simulator and not a real device. Eyes needs this information in order to operate correctly.

Ultrafast grid settings


web_ufg:runner_options:test_concurrency: 5

Set the maximum number of Eyes tests that can run concurrently when using the Ultrafast Grid.



Set this value to pass an option of the Ultrafast grid. For a list of possible values, see visual_grid_options property.


web_ufg:disable_browser_fetching: true

Under some circumstances, rendering of some resources may be missing. Set this value to true to eliminate these problems.


web_ufg:enable_cross_origin_rendering: false

Normally, when a webpage contains content from multiple sites, rendering of the page succeeds. If there are rendering errors due to incorrect rendering of content from other sites, set this value to false. When you do this, iframes that originate from other websites are rendered as blank pages.


web_ufg:dont_use_cookies: false

By default, cookie information in the browser is sent to the Ultrafast grid. Set this value to true to disable sending cookie information when sending checkpoint resources to the Ultrafast grid.


web_ufg:layout_breakpoints: true

Configure the SDK to capture multiple DOM images for multiple viewport sizes.

When the test loads a page into the test browser, the test browser loads the page, executes any JavaScript loaded with that page, and creates a DOM. The SDK then sends this DOM to the Ultrafast Grid, where it is rendered for each configured execution environment.

When the Ultrafast Grid sizes the browser, device emulator, or simulator to match the viewport size of the execution environment, all CSS is applied so that any viewport-width-dependent layouts have the expected effect. However, the on-page JavaScript is not executed. If the JavaScript impacts the DOM and is viewport-width-dependent, then the page may be rendered incorrectly.

Setting this field to true allows you to request that the SDK resize the test browser viewport to multiple viewport widths. Resizing the test browser viewport triggers re-execution of the on-page JavaScript and the creation of a viewport-width-specific DOM. The SDK then sends all of these DOMs to the Ultrafast Grid and the Ultrafast Grid renders each execution environment using the DOM that matches the environment viewport width of the execution environment.

Setting this YAML value to true enables this feature and extracts a DOM for every distinct viewport size configured. Alternatively, you can pass a list of distinct viewport widths, in which case the DOM is extracted for those particular viewport widths.

See Handling viewport-dependent JavaScript for more details.

Setting the Ultrafast grid execution environments

When using the Ultrafast grid, you must specify one or more execution environments. There are three types of environment, each with a list of supported devices. The three types are defined by the YAML fields web_ufg:browsers:desktop for a list of desktop browsers, web_ufg:browsers:ios IOS device simulation, and web_ufg:browsers:chrome_emulation for Chrome emulation.


    - browser_type: CHROME# values from BrowserType
       width: 1900
       height: 1800

For each browser, specify the browser type and the viewport width and height.


    -device_name: iPhone_12_Pro# names from IosDeviceName
      screen_orientation: PORTRAIT# PORTRAIT | LANDSCAPE
      ios_version: LATEST# LATEST | ONE_VERSION_BACK

For each IOS device to be simulated, specify the device name, the screen orientation (PORTRAIT or LANDSCAPE), and the ios version (LATEST or ONE_VERSION_BACK).


    - device_name: iPhone_4  # names from DeviceName
      screen_orientation: PORTRAIT  # PORTRAIT | LANDSCAPE