Network & Mocking

Inspect network traffic, mock API responses, and test offline behavior. Inspecting requests is part of core and always available. Mocking and network state control require the network capability.

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["@playwright/mcp@latest", "--caps=network"]
    }
  }
}

Inspect network requests

browser_network_requests

List requests made since page load. Part of core — no extra capability needed.

Parameter	Type	Required	Description
filter	string	no	Regexp pattern to filter URLs
includeStatic	boolean	no	Include images, CSS, fonts
includeBody	boolean	no	Include request body
includeHeaders	boolean	no	Include request headers

→ browser_network_requests { filter: "api" }

  GET  200 https://api.example.com/me              8ms   application/json
  POST 201 https://api.example.com/users/create     45ms  application/json
  GET  200 https://api.example.com/settings         12ms  application/json

Mock API responses

browser_route

Intercept requests matching a URL pattern and return a custom response.

Parameter	Type	Required	Description
pattern	string	yes	URL pattern (** glob supported)
status	number	no	HTTP status code
body	string	no	Response body
contentType	string	no	Content-Type header
headers	object	no	Additional response headers
removeHeaders	string[]	no	Headers to strip from request

Mock an API endpoint

You: Mock the /api/users endpoint to return two test users.

→ browser_route {
    pattern: "**/api/users",
    status: 200,
    body: "[{\"id\":1,\"name\":\"Alice\"},{\"id\":2,\"name\":\"Bob\"}]",
    contentType: "application/json"
  }
→ browser_reload
→ browser_snapshot
  - heading "Users" [level=1]
  - list "User list":
    - listitem: "Alice"
    - listitem: "Bob"

Test error handling

You: Test what happens when the API returns a 503 error.

→ browser_route { pattern: "**/api/users", status: 503 }
→ browser_reload
→ browser_snapshot
  - heading "Something went wrong" [level=1]
  - button "Retry" [ref=e5]

→ browser_take_screenshot

Remove the mock and verify recovery:

→ browser_unroute
→ browser_click { ref: "e5" }
→ browser_snapshot
  - heading "Users" [level=1]
  - list "User list":
    - listitem: "Alice Johnson"
    - listitem: "Bob Smith"

Block resources

→ browser_route { pattern: "**/*.jpg", status: 404 }
→ browser_route { pattern: "**/analytics/**", status: 204 }

Strip authentication headers

→ browser_route { pattern: "**/api/**", removeHeaders: ["cookie", "authorization"] }
→ browser_reload
  // Page shows 401 / login prompt

Conditional mocking with code

For complex scenarios — delays, conditional responses, request body inspection — use browser_run_code:

→ browser_run_code {
    code: "async (page) => {
      await page.route('**/api/search', async route => {
        const url = new URL(route.request().url());
        const query = url.searchParams.get('q');
        await route.fulfill({
          body: JSON.stringify(query === 'empty' ? [] : [{ title: 'Result: ' + query }])
        });
      });
    }"
  }

Manage routes

browser_route_list

→ browser_route_list

  Pattern              Status  Content-Type
  **/api/users         200     application/json
  **/*.jpg             404     -
  **/analytics/**      204     -

browser_unroute

Parameter	Type	Required	Description
pattern	string	no	Pattern to remove. Omit to remove all.

Test offline mode

browser_network_state_set

Parameter	Type	Required	Description
state	string	yes	online or offline

→ browser_network_state_set { state: "offline" }
→ browser_reload
→ browser_snapshot
  - heading "No internet connection" [level=1]

→ browser_network_state_set { state: "online" }
→ browser_reload
  // Page loads normally