[Answers](https://scrapfly.io/blog) / [selenium](https://scrapfly.io/blog/tag/selenium) / [How to block resources in Selenium and Python?](https://scrapfly.io/blog/answers/how-to-block-resources-in-selenium) # How to block resources in Selenium and Python? by [Bernardas Alisauskas](https://scrapfly.io/blog/author/bernardas) Jun 30, 2023 2 min read [\#selenium](https://scrapfly.io/blog/tag/selenium) [ ](https://www.linkedin.com/sharing/share-offsite/?url=https%3A%2F%2Fscrapfly.io%2Fblog%2Fanswers%2Fhow-to-block-resources-in-selenium "Share on LinkedIn") To speed up Selenium web scrapers we can block media and other non-essential background requests. Unfortunately, Selenium by itself doesn't support request interception and blocking so we must use a proxy to handle the blocking for us, then attach this proxy to our Selenium instance. For example, a popular proxy for such use case is [mitproxy](https://pypi.org/project/mitmproxy/). We can easily configure it to block requests by resource type or by resource name. First install mitmproxy using `pip install mitmproxy` or package manager available in your operating system. Then, we can create a simple `block.py` script that will extend mitmproxy with our custom blocking logic: python```python # block.py from mitmproxy import http # we can block popular 3rd party resources like tracking and advertisements. BLOCK_RESOURCE_NAMES = [ 'adzerk', 'analytics', 'cdn.api.twitter', 'doubleclick', 'exelator', 'facebook', 'fontawesome', 'google', 'google-analytics', 'googletagmanager', # or something abstract like images 'images' ] # or block based on resource extension BLOCK_RESOURCE_EXTENSIONS = [ '.gif', '.jpg', '.jpeg', '.png', '.webp', ] # this will handle all requests going through proxy: def request(flow: http.HTTPFlow) -> None: url = flow.request.pretty_url has_blocked_extension = any(url.endswith(ext) for ext in BLOCK_RESOURCE_EXTENSIONS) contains_blocked_key = any(block in url for block in BLOCK_RESOURCE_NAMES) if has_blocked_extension or contains_blocked_key: print(f"Blocked {url}") flow.response = http.Response.make( 404, # status code b"Blocked", # content {"Content-Type": "text/html"} # headers ) ``` We can run this proxy using `mitmproxy -s block.py` and it'll start a proxy on `localhost:8080` on our machine. Now, we can attach this proxy to our Selenium instance and it'll block all unwanted requests going through it: python```python from selenium import webdriver PROXY = "localhost:8080" # IP:PORT or HOST:PORT of our mitmproxy chrome_options = webdriver.ChromeOptions() # this command enabled proxy for our Selenium browser: chrome_options.add_argument('--proxy-server=%s' % PROXY) chrome = webdriver.Chrome(options=chrome_options) # test it by going to a page with blocked resources: chrome.get("https://web-scraping.dev/product/1") chrome.quit() ``` Using this method to block resources can significantly reduce the bandwidth used by the Selenium scraper - often by 2-10 times! This will also greatly speed up scraping as the browser doesn't need to render unnecessary resources. 🤖 Tip: to use `mitmproxy` with Selenium and `https` websites the mitmproxy certificate needs to be installed for that see [how to install mitmproxy certificate](https://scrapfly.io/blog/answers/how-to-install-mitmproxy-certificate) Scale Your Web Scraping Anti-bot bypass, browser rendering, and rotating proxies, all in one API. Start with 1,000 free credits. No credit card required 1,000 free API credits Anti-bot bypass included [Start Free](https://scrapfly.io/register) [View Docs](https://scrapfly.io/docs/onboarding) Not ready? 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