Source: https://playwright.dev/python/docs/network

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Introduction​

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Playwright provides APIs to monitor and modify browser network traffic, both HTTP and HTTPS. Any requests that a page does, including XHRs and fetch requests, can be tracked, modified and handled.

Mock APIs​

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Check out our API mocking guide to learn more on how to

• mock API requests and never hit the API
• perform the API request and modify the response
• use HAR files to mock network requests.

HTTP Authentication​

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Perform HTTP Authentication.

• Sync

• Async

  context = browser.new_context( http_credentials={"username": "bill", "password": "pa55w0rd"})page = context.new_page()page.goto("https://example.com")

  context = await browser.new_context( http_credentials={"username": "bill", "password": "pa55w0rd"})page = await context.new_page()await page.goto("https://example.com")

HTTP Proxy​

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You can configure pages to load over the HTTP(S) proxy or SOCKSv5. Proxy can be either set globally for the entire browser, or for each browser context individually.

You can optionally specify username and password for HTTP(S) proxy, you can also specify hosts to bypass the proxy for.

Here is an example of a global proxy:

• Sync

• Async

  browser = chromium.launch(proxy={ "server": "http://myproxy.com:3128", "username": "usr", "password": "pwd"})

  browser = await chromium.launch(proxy={ "server": "http://myproxy.com:3128", "username": "usr", "password": "pwd"})

Its also possible to specify it per context:

• Sync

• Async

  browser = chromium.launch()context = browser.new_context(proxy={"server": "http://myproxy.com:3128"})

  browser = await chromium.launch()context = await browser.new_context(proxy={"server": "http://myproxy.com:3128"})

Network events​

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You can monitor all the Request s and Response s:

• Sync

• Async

  from playwright.sync_api import sync_playwright, Playwrightdef run(playwright: Playwright): chromium = playwright.chromium browser = chromium.launch() page = browser.new_page() # Subscribe to "request" and "response" events. page.on("request", lambda request: print(">>", request.method, request.url)) page.on("response", lambda response: print("<<", response.status, response.url)) page.goto("https://example.com") browser.close()with sync_playwright() as playwright: run(playwright)

  import asynciofrom playwright.async_api import async_playwright, Playwrightasync def run(playwright: Playwright): chromium = playwright.chromium browser = await chromium.launch() page = await browser.new_page() # Subscribe to "request" and "response" events. page.on("request", lambda request: print(">>", request.method, request.url)) page.on("response", lambda response: print("<<", response.status, response.url)) await page.goto("https://example.com") await browser.close()async def main(): async with async_playwright() as playwright: await run(playwright)asyncio.run(main())

Or wait for a network response after the button click with page.expect_response() :

• Sync

• Async

  Use a glob url patternwith page.expect_response("**/api/fetch_data") as response_info: page.get_by_text("Update").click()response = response_info.value

  Use a glob url patternasync with page.expect_response("**/api/fetch_data") as response_info: await page.get_by_text("Update").click()response = await response_info.value

Variations​

Wait for Response s with page.expect_response()

• Sync

• Async

  Use a regular expressionwith page.expect_response(re.compile(r".jpeg$")) as response_info: page.get_by_text("Update").click()response = response_info.value# Use a predicate taking a response objectwith page.expect_response(lambda response: token in response.url) as response_info: page.get_by_text("Update").click()response = response_info.value

  Use a regular expressionasync with page.expect_response(re.compile(r".jpeg$")) as response_info: await page.get_by_text("Update").click()response = await response_info.value# Use a predicate taking a response objectasync with page.expect_response(lambda response: token in response.url) as response_info: await page.get_by_text("Update").click()response = await response_info.value

Handle requests​

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• Sync

• Async

  page.route( "**/api/fetch_data", lambda route: route.fulfill(status=200, body=test_data))page.goto("https://example.com")

  await page.route( "**/api/fetch_data", lambda route: route.fulfill(status=200, body=test_data))await page.goto("https://example.com")

You can mock API endpoints via handling the network requests in your Playwright script.

Variations​

Set up route on the entire browser context with browser_context.route() or page with page.route() . It will apply to popup windows and opened links.

• Sync

• Async

  context.route( "**/api/login", lambda route: route.fulfill(status=200, body="accept"))page.goto("https://example.com")

  await context.route( "**/api/login", lambda route: route.fulfill(status=200, body="accept"))await page.goto("https://example.com")

Modify requests​

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• Sync

• Async

  Delete headerdef handle_route(route): headers = route.request.headers del headers["x-secret"] route.continue_(headers=headers)page.route("/*", handle_route)# Continue requests as POST.page.route("/*", lambda route: route.continue_(method="POST"))

  Delete headerasync def handle_route(route): headers = route.request.headers del headers["x-secret"] await route.continue_(headers=headers)await page.route("/*", handle_route)# Continue requests as POST.await page.route("/*", lambda route: route.continue_(method="POST"))

You can continue requests with modifications. Example above removes an HTTP header from the outgoing requests.

Abort requests​

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You can abort requests using page.route() and route.abort() .

• Sync

• Async

  page.route("/*.{png,jpg,jpeg}", lambda route: route.abort())# Abort based on the request typepage.route("/*", lambda route: route.abort() if route.request.resource_type == "image" else route.continue_())

  await page.route("/*.{png,jpg,jpeg}", lambda route: route.abort())# Abort based on the request typeawait page.route("/*", lambda route: route.abort() if route.request.resource_type == "image" else route.continue_())

Modify responses​

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To modify a response use APIRequestContext to get the original response and then pass the response to route.fulfill() . You can override individual fields on the response via options:

• Sync

• Async

  def handle_route(route: Route) -> None: # Fetch original response. response = route.fetch() # Add a prefix to the title. body = response.text() body = body.replace("<title>", "<title>My prefix:") route.fulfill( # Pass all fields from the response. response=response, # Override response body. body=body, # Force content type to be html. headers={response.headers, "content-type": "text/html"}, )page.route("/title.html", handle_route)

  async def handle_route(route: Route) -> None: # Fetch original response. response = await route.fetch() # Add a prefix to the title. body = await response.text() body = body.replace("<title>", "<title>My prefix:") await route.fulfill( # Pass all fields from the response. response=response, # Override response body. body=body, # Force content type to be html. headers={response.headers, "content-type": "text/html"}, )await page.route("/title.html", handle_route)

Glob URL patterns​

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Playwright uses simplified glob patterns for URL matching in network interception methods like page.route() or page.expect_response() . These patterns support basic wildcards:

1. Asterisks:
   • A single * matches any characters except /
   • A double ** matches any characters including /
2. Question mark ? matches only question mark ?. If you want to match any character, use * instead.
3. Curly braces {} can be used to match a list of options separated by commas ,
4. Backslash \ can be used to escape any of special characters (note to escape backslash itself as \\)

Examples:

• https://example.com/*.js matches https://example.com/file.js but not https://example.com/path/file.js
• https://example.com/?page=1 matches https://example.com/?page=1 but not https://example.com
• **/*.js matches both https://example.com/file.js and https://example.com/path/file.js
• **/*.{png,jpg,jpeg} matches all image requests

Important notes:

• The glob pattern must match the entire URL, not just a part of it.
• When using globs for URL matching, consider the full URL structure, including the protocol and path separators.
• For more complex matching requirements, consider using [RegExp] instead of glob patterns.

WebSockets​

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Playwright supports WebSockets inspection, mocking and modifying out of the box. See our API mocking guide to learn how to mock WebSockets.

Every time a WebSocket is created, the page.on("websocket") event is fired. This event contains the WebSocket instance for further web socket frames inspection:

def on_web_socket(ws):    print(f"WebSocket opened: {ws.url}")    ws.on("framesent", lambda payload: print(payload))    ws.on("framereceived", lambda payload: print(payload))    ws.on("close", lambda payload: print("WebSocket closed"))page.on("websocket", on_web_socket)

Missing Network Events and Service Workers​

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Playwright's built-in browser_context.route() and page.route() allow your tests to natively route requests and perform mocking and interception.

1. If you're using Playwright's native browser_context.route() and page.route() , and it appears network events are missing, disable Service Workers by setting service_workers to 'block'.
2. It might be that you are using a mock tool such as Mock Service Worker (MSW). While this tool works out of the box for mocking responses, it adds its own Service Worker that takes over the network requests, hence making them invisible to browser_context.route() and page.route() . If you are interested in both network testing and mocking, consider using built-in browser_context.route() and page.route() for response mocking .
3. If you're interested in not solely using Service Workers for testing and network mocking, but in routing and listening for requests made by Service Workers themselves, please see this experimental feature .

• Introduction

• Mock APIs

• HTTP Authentication

• HTTP Proxy

• Network events

• Handle requests

• Modify requests

• Abort requests

• Modify responses

• Glob URL patterns

• WebSockets

• Missing Network Events and Service Workers