# Choose browser, viewport, and configuration

Run configurations control how Playwright opens your application. They define settings such as browser, viewport, screenshots, video, traces, reporters, and other execution options.

You select at least one run configuration before starting a run.

## What a run configuration controls

Most teams use configurations to answer questions like:

| Question                         | Example                                                         |
| -------------------------------- | --------------------------------------------------------------- |
| Which browser should run?        | Chromium, Firefox, WebKit, or a named project.                  |
| What screen size should be used? | Desktop, tablet, mobile, or a custom viewport.                  |
| What evidence should be saved?   | Screenshots, videos, traces, console logs, and network records. |
| How should tests report results? | HTML, JSON, JUnit, blob, or console output.                     |
| How many tests can run at once?  | A worker count or parallelization setting.                      |

The default TestVibe template usually starts with a desktop Chromium configuration and saves evidence on failure. Your repository may have additional configurations such as cross-browser, responsive, staging, or smoke-test presets.

## Choose a configuration for a run

1. Open **Runs**.
2. Select **New Run**.
3. Choose the tests you want to execute.
4. Enter the **Site URL**.
5. Select one or more **Run Configurations**.
6. Start the run.

The selected configuration is attached to that run. When you re-run the same test later, confirm the configuration still matches the environment and browser coverage you want.

## Browser and viewport strategy

Use a small set of clear configurations instead of many overlapping options.

| Configuration type | Use it for                                                                          |
| ------------------ | ----------------------------------------------------------------------------------- |
| Desktop default    | Fast daily validation in the team's primary browser size.                           |
| Responsive         | Mobile or tablet layouts where navigation and layout behavior changes.              |
| Cross-browser      | Compatibility checks across browser engines.                                        |
| Debug              | More evidence, lower parallelism, or settings that make failures easier to inspect. |
| Release            | Broader coverage before a release or deployment.                                    |

## Manage configurations

Repository configurations are managed from **Settings > Configurations**. From there, you can add, edit, or review the Playwright configuration files TestVibe uses during runs.

For runner selection, see [Runners](/runners.md).


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