How to Monitor Website Changes Automatically (Visual Diff Tutorial)

How to Monitor Website Changes Automatically I run a few websites and need to know immediately when something breaks. A CSS regression, a broken layout, a missing section. Manual checking doesn't scale, and text-based monitoring misses visual issues. The {{screenshot-diff}} on Apify takes two screenshots and produces a pixel-level comparison with an overlay showing exactly what changed. How It Works Take a baseline screenshot of the correct state. Then take a current screenshot of the live page. The actor compares pixel by pixel and returns a diff image with changed pixels highlighted, plus a percentage telling you how much changed. import requests , time API_TOKEN = " YOUR_APIFY_TOKEN " def capture_screenshot ( url ): resp = requests . post ( " https://api.apify.com/v2/acts/weeknds~website-screenshot-api/runs " , headers = { " Authorization " : f " Bearer { API_TOKEN } " }, json = { " url " : url , " fullPage " : True } ) run_id = resp . json ()[ " data " ][ " id " ] time . sleep ( 15 ) items = requests . get ( f " https://api.apify.com/v2/acts/weeknds~website-screenshot-api/runs/ { run_id } /dataset/items " , headers = { " Authorization " : f " Bearer { API_TOKEN } " } ). json () return items [ 0 ][ " screenshotUrl " ] def compare_screenshots ( baseline_url , current_url ): resp = requests . post ( " https://api.apify.com/v2/acts/weeknds~screenshot-comparison-tool/runs " , headers = { " Authorization " : f " Bearer { API_TOKEN } " }, json = { " baselineImageUrl " : baseline_url , " currentImageUrl " : current_url , " threshold " : 0.01 } ) run_id = resp . json ()[ " data " ][ " id " ] time . sleep ( 10 ) items = requests . get ( f " https://api.apify.com/v2/acts/weeknds~screenshot-comparison-tool/runs/ { run_id } /dataset/items " , headers = { " Authorization " : f " Bearer { API_TOKEN } " } ). json () return items [ 0 ] baseline = capture_screenshot ( " https://mysite.com " ) current = capture_screenshot ( " https://mysite.com " ) result = compare_screenshots ( b