--- title: Compression Monitoring for Brotli description: Compression monitoring by WatchFor. Check that your pages and assets still come back with Content-Encoding: br when a client asks for Brotli, and get alerted when a CDN or deploy turns it off. canonical: https://watchfor.io/compression-monitoring --- # Compression Monitoring for Brotli Catch pages and assets that stop coming back Brotli-compressed, from a CDN that strips the encoding to a deploy that quietly turns it off, before they slow your site and inflate your bandwidth bill. [Get started for free](/auth/sign-up)[View pricing](/pricing) ## Compression Monitoring Features One question per URL, answered on every check: is Brotli on? ### Content-Encoding Check Each check requests your URL with Accept-Encoding: br, follows any redirects and reads the Content-Encoding header that comes back. ### Brotli Not Supported Alert On by default at warning severity, this rule fires when the server stops returning br to a client that asked for it. Raise it to critical if Brotli matters to you. ### What Came Back Instead Each check keeps the exact Content-Encoding value the server returned, or shows there was none, so an incident tells you what changed. ### One URL per Monitor Servers and CDNs apply compression rules by file type. Add a monitor for your HTML page, your main JavaScript bundle and your CSS, and each gets its own alert. ### Checks From Your Regions Checks run from the regions you choose (your plan sets how many), so a CDN edge that serves responses without Brotli shows up in that location's results. ### Confirmed Alerts Failures are confirmed from several locations before an incident opens, so one odd response doesn't page anyone. ### Supported Rate Over Time See the encoding of every check and the share of checks that came back with Brotli, handy for pinning down the deploy or CDN change that turned it off. ### Flexible Scheduling Check as often as every 30 minutes or as rarely as once a day, and use maintenance windows so planned CDN work never triggers alerts. ## A closer look When Brotli goes missing, the incident shows what was expected and seen. Brotli Not Supported is its own rule, with warning or critical severity. ## Why Choose Our Compression Monitoring Solution? Compression is one of the cheapest wins for web performance, and it fails silently. A misconfigured server, a CDN that strips the encoding or a framework upgrade can drop Brotli without throwing a single error; responses just get bigger. Our monitor asks for Brotli, reads the Content-Encoding header and alerts you when br stops coming back. It checks Brotli only: it doesn't test the gzip fallback or measure response sizes. [Start monitoring now](/auth/sign-up) Check Brotli on any public page or asset Read the Content-Encoding header on every check Brotli Not Supported rule, on by default Catch CDNs and proxies that strip the encoding Checks from the regions your plan includes Failures confirmed from several locations Every 30 minutes on the Starter plan and above Alerts on any of 16 channels, including email, Slack and PagerDuty ## How Compression Monitoring Works From URL to alert in four steps 1 ### Add Your URL Enter the page or asset URL you want to check and pick the regions you want to test from. 2 ### Choose Severity Brotli Not Supported is on by default at warning severity. Raise it to critical, and set how many failed checks confirm a problem. 3 ### Monitor 24/7 We request the URL with Accept-Encoding: br, follow any redirects and read the Content-Encoding header on every check. 4 ### Get Alerts When Brotli stops coming back, you're notified on your channels, and the incident shows the encoding the server sent instead. ## Compression Monitoring Use Cases For any site that cares about speed and bandwidth ### Guard Page Speed Uncompressed or gzip-only HTML, CSS and JavaScript take longer to arrive and can hurt Core Web Vitals. A monitor on your largest text assets tells you when Brotli drops off. ### Verify CDN Configuration CDNs and reverse proxies sometimes strip or fail to apply compression at the edge. Checking from more than one region confirms the edge serves Brotli the way your origin intended. ### Catch Deploy Regressions A new build, framework upgrade or server tweak can silently disable Brotli on some routes. Get alerted soon after a deploy starts shipping responses without it. ### Control Bandwidth Costs Every byte compression doesn't remove is bandwidth you pay for and your users wait on. Knowing Brotli stayed on is the cheap part of keeping that bill down. ## Frequently asked questions Everything you need to know about compression monitoring [All questions→](/faq)[Ask us directly](/contact) What is compression monitoring? Compression monitoring checks that your server still serves Brotli. Each check requests the URL with Accept-Encoding: br and reads the Content-Encoding header of the response. If Brotli stops coming back, you get an alert, because nothing else visibly breaks when compression is lost. What's the difference between Brotli and Gzip? What does each check record? Why does missing compression matter? Can a CDN break my compression? Does it check every file on my site? How often are compression checks performed? What happens when compression breaks? Can I monitor internal or private URLs? ## From our blog Guides, deep-dives, and best practices from the WatchFor team [Performance ### Gzip vs Brotli: web compression compared Jan 15, 2026·3 min readRead article](/blog/gzip-vs-brotli)[Performance ### How to Speed Up Your Website (the high-impact wins first) Jan 31, 2026·3 min readRead article](/blog/how-to-speed-up-your-website)[Performance ### Image Optimization for the Web (the biggest easy win) Jan 21, 2026·3 min readRead article](/blog/image-optimization) ## Ready to Keep Brotli On? Compression monitors are included from the Starter plan. Run the free Brotli checker first, or sign up for free and upgrade when you add your first monitor. [Get started for free](/auth/sign-up)[View documentation](/docs/monitors/performance#brotli-compression) --- Canonical page: https://watchfor.io/compression-monitoring · Site guide: https://watchfor.io/llms.txt