Technical insights on web performance, automatic optimization, and the engineering behind ModPageSpeed.https://modpagespeed.com/en-usSat, 04 Jul 2026 00:00:00 GMThttps://modpagespeed.com/blog/cyclone-cache-vs-file-cache-benchmark/https://modpagespeed.com/blog/cyclone-cache-vs-file-cache-benchmark/Head-to-head cache benchmark: Cyclone (memory-mapped, in-process RAM tier) vs. the classic file-per-entry cache, across concurrency, realistic traffic, latency tails, and eviction, on fast and realistic storage.Sat, 04 Jul 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/agentic-web-at-the-origin/https://modpagespeed.com/blog/agentic-web-at-the-origin/The agentic web creates four origin problems: identity, economics, what to serve, provenance. Where to solve them, and why on your own servers.Mon, 22 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/pay-per-crawl-at-the-origin/https://modpagespeed.com/blog/pay-per-crawl-at-the-origin/mod_pagespeed 1.15 ships an experimental, off-by-default RSL-CAP gate for nginx: validate Authorization: License capability tokens and refuse unauthorized AI-crawler access at your origin. Preview, not GA.Mon, 22 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/preserve-content-credentials-c2pa/https://modpagespeed.com/blog/preserve-content-credentials-c2pa/ModPageSpeed detects C2PA / Content Credentials manifests and preserves image provenance instead of stripping it during optimization — on by default in both engines.Mon, 22 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/serve-markdown-to-ai-agents/https://modpagespeed.com/blog/serve-markdown-to-ai-agents/ModPageSpeed 2.0 serves a clean markdown variant on Accept: text/markdown and synthesizes an /llms.txt index from your sitemap, generated at your own origin. Experimental, 2.0-only, license-gated, off by default.Mon, 22 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/verify-ai-crawlers-web-bot-auth/https://modpagespeed.com/blog/verify-ai-crawlers-web-bot-auth/mod_pagespeed 1.15 ships an nginx Web Bot Auth verifier that checks RFC 9421 signatures and labels each request in $x_verified_bot. Observe-only, default off.Mon, 22 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/air-gapped-headless-fetch-ssrf-pinning/https://modpagespeed.com/blog/air-gapped-headless-fetch-ssrf-pinning/SSRF protection for headless browser rendering: ModPageSpeed 2.0 forces Chrome offline, routing subresources through an IP-pinned fetch re-checked per redirect.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/cache-key-url-normalization-tracking-params/https://modpagespeed.com/blog/cache-key-url-normalization-tracking-params/Strip tracking parameters to stop cache fragmentation: ModPageSpeed normalizes the URL before keying, dropping UTM params, sorting the query, aliasing hosts.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/default-cache-ttl-heuristic-freshness/https://modpagespeed.com/blog/default-cache-ttl-heuristic-freshness/Default cache TTL when no Cache-Control: per-content-type heuristic TTLs, RFC 9111 Age adjustment, and the shared-vs-private cache split in ModPageSpeed 2.0.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/headless-lcp-cls-measurement/https://modpagespeed.com/blog/headless-lcp-cls-measurement/Headless LCP and CLS measurement in ModPageSpeed 2.0: injected PerformanceObservers capture the real LCP element and layout shifts to drive preload hints.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/proactive-variant-generation-cache-warmup/https://modpagespeed.com/blog/proactive-variant-generation-cache-warmup/How ModPageSpeed 2.0 warms hot-URL caches: nginx flags a hot URL and the worker pre-builds the whole image variant matrix — format, viewport, density, Save-Data — instead of encoding one variant per request.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/remove-unused-javascript-chrome-coverage/https://modpagespeed.com/blog/remove-unused-javascript-chrome-coverage/How a headless Chrome V8 coverage pass measures which JavaScript actually executes before first paint, so ModPageSpeed 2.0 can safely defer the scripts that never run on load.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/safe-javascript-minification-semicolon-insertion/https://modpagespeed.com/blog/safe-javascript-minification-semicolon-insertion/To minify JavaScript safely you have to parse it, not strip whitespace. How ModPageSpeed 2.0's tokenizer handles automatic semicolon insertion, regex-vs-divide, and a parse-error fail-safe that ships the original untouched.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/serve-markdown-to-ai-crawlers-llms-txt/https://modpagespeed.com/blog/serve-markdown-to-ai-crawlers-llms-txt/How to serve markdown to AI crawlers on the same URL via Accept: text/markdown, synthesize /llms.txt from the sitemap, and honor AI opt-out directives.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/server-injected-resource-hints-speculation-rules/https://modpagespeed.com/blog/server-injected-resource-hints-speculation-rules/How a proxy generates server-injected resource hints: speculation-rules prefetch derived from real traffic, priority-bucketed preconnect, font preload.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/ssimulacra2-image-quality-verification/https://modpagespeed.com/blog/ssimulacra2-image-quality-verification/How ModPageSpeed 2.0 scores encoded images against a SSIMULACRA2 image quality target and re-encodes until the result clears tolerance, not a quality knob.Sun, 14 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/cache-key-derivation-and-alternate-fallback/https://modpagespeed.com/blog/cache-key-derivation-and-alternate-fallback/How cache key derivation in ModPageSpeed 2.0 hashes host plus URL into one key and scores stored variants in one selector pass instead of probing many keys.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/cache-mode-safety-must-revalidate-vs-aggressive/https://modpagespeed.com/blog/cache-mode-safety-must-revalidate-vs-aggressive/Cache-Control safety in ModPageSpeed 2.0: why must-revalidate, not max-age, is the real safety net, and when aggressive TTLs with stale-if-error and stale-while-revalidate are the right call.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/conditional-revalidation-304-vs-active-purge/https://modpagespeed.com/blog/conditional-revalidation-304-vs-active-purge/Conditional revalidation vs purge: when a 304 ETag round-trip beats PURGE and preserves optimized AVIF/WebP variants on an HTML-only deploy with no rebuild.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/critical-css-beacon-to-headless-history/https://modpagespeed.com/blog/critical-css-beacon-to-headless-history/How critical CSS extraction works without a build step: the original beacon model, why CDNs broke it, and how 2.0 moved to heuristics + headless Chrome.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/css-cache-inlining-for-coverage-api/https://modpagespeed.com/blog/css-cache-inlining-for-coverage-api/How ModPageSpeed 2.0 feeds the Chrome Coverage API critical CSS: inline cached stylesheets into a network-blocked sandbox so it reports real used vs unused CSS.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fire-and-forget-worker-ipc/https://modpagespeed.com/blog/fire-and-forget-worker-ipc/ModPageSpeed 2.0 keeps optimization work off the nginx request path with fire-and-forget IPC to the worker: a small notification, no reply, so a cache miss stays cheap and requests never wait on an encode.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/flatten-css-imports-edge-cases/https://modpagespeed.com/blog/flatten-css-imports-edge-cases/Why flattening CSS @import rules is harder than concatenation: media intersection, @charset aborts, url() rebasing, and the CssFlattenMaxBytes cap.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/image-content-classification-and-denoise/https://modpagespeed.com/blog/image-content-classification-and-denoise/Content-aware image optimization classifies decoded images and denoises noisy sources before encoding, so photos, screenshots, and logos get the right codec.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/memory-mapped-cache-zero-copy-serving/https://modpagespeed.com/blog/memory-mapped-cache-zero-copy-serving/How ModPageSpeed 2.0 shares one memory-mapped cache between nginx and the worker, serving large cache hits zero-copy with kernel sendfile and small ones with a single copy, while staying correct under concurrent writes.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/mod-pagespeed-content-security-policy/https://modpagespeed.com/blog/mod-pagespeed-content-security-policy/Does mod_pagespeed break a strict Content-Security-Policy? Where automatic rewriting collides with a CSP, feature by feature, and how the HonorCsp directive keeps optimized pages policy-compliant.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/sentinel-cache-keys-and-103-early-hints/https://modpagespeed.com/blog/sentinel-cache-keys-and-103-early-hints/How ModPageSpeed 2.0 precomputes 103 Early Hints preloads and lets nginx serve them from cache, using sentinel cache keys — the reserved Viewport=3 trick — to store them alongside per-URL content variants.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/single-url-cache-purge-optimizing-proxy/https://modpagespeed.com/blog/single-url-cache-purge-optimizing-proxy/Purging one URL in ModPageSpeed touches more than one cache entry. The fan-out problem, the lookup-time design 1.x used, and why 2.0 deletes immediately.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/svg-auto-vectorization/https://modpagespeed.com/blog/svg-auto-vectorization/Raster to SVG auto-vectorization in ModPageSpeed 2.0 traces qualifying logos and icons with VTracer, collapsing the @1x/@2x/viewport matrix into one variant.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/template-hashing-critical-css-reuse/https://modpagespeed.com/blog/template-hashing-critical-css-reuse/How ModPageSpeed 2.0 hashes a page template so critical CSS is computed once and reused across every URL sharing that template, with analysis-queue dedup to skip redundant renders.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/visual-regression-gating-optimizations/https://modpagespeed.com/blog/visual-regression-gating-optimizations/ModPageSpeed 2.0 pixel-diffs the rendered above-fold before caching a headless critical-CSS variant. If the optimized page looks different, the gate discards it and keeps the heuristic version.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/wordpress-server-side-page-cache-plugin/https://modpagespeed.com/blog/wordpress-server-side-page-cache-plugin/How a WordPress server-side page cache plugin sets Cache-Control on anonymous pages and purges the ModPageSpeed cache on publish, instead of caching in PHP.Sat, 13 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/search-console-ai-performance-report-vs-page-speed/https://modpagespeed.com/blog/search-console-ai-performance-report-vs-page-speed/Google's new Search Console AI performance report measures your visibility in AI Overviews and AI Mode, not how fast your pages load. The difference, explained.Tue, 09 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/avif-vs-webp-2026/https://modpagespeed.com/blog/avif-vs-webp-2026/AVIF beats WebP on size but is slower to encode. In 2026, serve AVIF, WebP, or the original per request off the Accept header instead of picking one format for everyone.Sat, 06 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/learned-quality-prediction/https://modpagespeed.com/blog/learned-quality-prediction/One perception-based quality knob; a trained model predicts the right JPEG, WebP, and AVIF encoding parameters per image in microseconds. No per-codec tuning, self-hosted.Sat, 06 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/nginx-image-optimization-module/https://modpagespeed.com/blog/nginx-image-optimization-module/A native nginx module that transcodes images to WebP on serve, content-negotiates on Accept, and caches the variant. Install from signed apt/yum, no compiling.Sat, 06 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/ngx-pagespeed-wont-build-modern-nginx/https://modpagespeed.com/blog/ngx-pagespeed-wont-build-modern-nginx/Why upstream ngx_pagespeed won't compile on nginx 1.25+ (sys_siglist, glibc, OpenSSL 3, toolchain drift) — and the prebuilt module to install instead.Sat, 06 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/reduce-ttfb-server-layer-2026/https://modpagespeed.com/blog/reduce-ttfb-server-layer-2026/Reduce TTFB on nginx: split origin compute, network, and cache, then fix keep-alive, HTTP/2 or HTTP/3, TLS resumption, and variant-aware caching.Sat, 06 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/self-hosted-image-optimization/https://modpagespeed.com/blog/self-hosted-image-optimization/Image SaaS bills per transformation and per GB of egress. Self-hosted optimization transcodes WebP/AVIF on your servers at a flat per-site cost — no third party.Sat, 06 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/content-hash-urls/https://modpagespeed.com/blog/content-hash-urls/A content hash in a .pagespeed. URL gives mod_pagespeed year-long caching with automatic cache busting — the same idea webpack contenthash and Cache-Control: immutable landed on later. Plus what data-pagespeed-url-hash actually is.Fri, 05 Jun 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/can-ai-read-your-website/https://modpagespeed.com/blog/can-ai-read-your-website/40% of the top 1,000 sites serve almost nothing to non-JavaScript AI crawlers — ChatGPT, Perplexity, and Claude see an empty page. The data, and how to fix it.Thu, 28 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/aspnet-core-image-optimization-c-sharp/https://modpagespeed.com/blog/aspnet-core-image-optimization-c-sharp/Serve WebP and AVIF from ASP.NET Core with no controller or Razor changes. WeAmp.PageSpeed middleware does Accept-header content negotiation, viewport sizing, and LCP preload.Wed, 20 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-inp-aspnet-core-2026/https://modpagespeed.com/blog/fix-inp-aspnet-core-2026/How to fix INP on ASP.NET Core: Razor + jQuery responds well to bundling and the WeAmp.PageSpeed middleware; Blazor Server INP is architectural and needs WASM.Wed, 20 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/google-dl-ssl-mod-pagespeed-download/https://modpagespeed.com/blog/google-dl-ssl-mod-pagespeed-download/The dl-ssl.google.com mod_pagespeed .deb is Google's last stable build, 1.13.35.2 (2018), with years of unpatched CVEs. Get the maintained download for Apache, nginx, and IIS instead.Wed, 20 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/mod-pagespeed-deprecated-2026/https://modpagespeed.com/blog/mod-pagespeed-deprecated-2026/Yes, mod_pagespeed is deprecated: the 1.13.35.2 binaries run but haven't had security updates in years. What to use instead on Apache, nginx, IIS, and ASP.NET Core.Wed, 20 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/run-with-docker-compose/https://modpagespeed.com/blog/run-with-docker-compose/A working docker-compose.yml for ModPageSpeed 2.0 on nginx: worker + interceptor + shared Cyclone cache volume. Verify with curl, apply a license, done.Wed, 20 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/server-side-critical-css-nginx/https://modpagespeed.com/blog/server-side-critical-css-nginx/Extract and inline critical CSS at the nginx layer for any backend (PHP, Rails, Django, ASP.NET, Go). No WordPress plugin. No headless browser. No Node build step.Wed, 20 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-cls-aspnet-core-2026/https://modpagespeed.com/blog/fix-cls-aspnet-core-2026/How to fix CLS on ASP.NET Core: pre-size async view components, persist image dimensions, reserve banner space, rewrite img tags via middleware.Tue, 19 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-lcp-aspnet-core-2026/https://modpagespeed.com/blog/fix-lcp-aspnet-core-2026/Fix Largest Contentful Paint on ASP.NET Core: async view components, immutable cache headers, deferred JS, and the WeAmp.PageSpeed middleware — for Razor Pages, MVC, and Blazor Server.Mon, 18 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/mod-pagespeed-1-1-release/https://modpagespeed.com/blog/mod-pagespeed-1-1-release/mod_pagespeed 1.15 ships 765 merges since 1.13.35.2: image-decoder hardening, a full sanitizer matrix, a current dependency graph, and the IIS port in the C++ tree.Sun, 17 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-inp-nginx-2026/https://modpagespeed.com/blog/fix-inp-nginx-2026/How to fix INP on nginx: a CMS-agnostic guide. Server-layer JS minification helps if your JS is bloated; if your stack is already lean, the wins are upstream.Thu, 14 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-cls-nginx-2026/https://modpagespeed.com/blog/fix-cls-nginx-2026/Fix Cumulative Layout Shift on nginx-served sites: rewrite img tags to add width/height with ngx_pagespeed (mod_pagespeed 1.15), add a CSS aspect-ratio backstop, and ship dimensions at build time.Tue, 12 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-lcp-nginx-2026/https://modpagespeed.com/blog/fix-lcp-nginx-2026/How to fix LCP on nginx: HTTP/2, gzip_static, TLS resumption, and the mod_pagespeed rewriter. Stack-agnostic LCP fixes that work behind any backend in 2026.Thu, 07 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-inp-magento-2026/https://modpagespeed.com/blog/fix-inp-magento-2026/Fixing INP on Magento 2: the interaction cost lives in KnockoutJS and RequireJS, so theme architecture (Hyvä) moves it, not a server rewriter — plus exactly what mod_pagespeed can and cannot do.Tue, 05 May 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-cls-magento-2026/https://modpagespeed.com/blog/fix-cls-magento-2026/Fix Cumulative Layout Shift on Magento 2 product pages: stop Fotorama gallery jumps, pre-size the mini-cart and private-content blocks, and write img dimensions at the server layer.Thu, 30 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-lcp-magento-2026/https://modpagespeed.com/blog/fix-lcp-magento-2026/How to fix LCP on Magento: tame the RequireJS waterfall, regenerate catalog images, inline critical CSS at the server. Step-by-step for Magento 2 in 2026.Tue, 28 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-inp-woocommerce-2026/https://modpagespeed.com/blog/fix-inp-woocommerce-2026/How to fix INP on WooCommerce: server-layer JS minification reduces the parse cost, but cart and variation handlers are architectural.Thu, 23 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-cls-woocommerce-2026/https://modpagespeed.com/blog/fix-cls-woocommerce-2026/How to fix CLS on WooCommerce: stop the gallery shift, lock variation swap dimensions, reserve cross-sell space, and rewrite img tags at the server.Tue, 21 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-lcp-woocommerce-2026/https://modpagespeed.com/blog/fix-lcp-woocommerce-2026/Fix LCP on WooCommerce: shrink the product gallery, drop cart-fragments on non-shop pages, and rewrite catalog images at the server with mod_pagespeed.Thu, 16 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-inp-wordpress-2026/https://modpagespeed.com/blog/fix-inp-wordpress-2026/How to fix INP on WordPress: diagnose the responsible interaction, defer non-critical JS at the server layer, then trim plugin handlers and jQuery.Tue, 14 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-cls-wordpress-2026/https://modpagespeed.com/blog/fix-cls-wordpress-2026/How to fix CLS on WordPress: diagnose the shifts, set width/height on every image at the server layer, lock down fonts, reserve banner space.Fri, 10 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/fix-lcp-wordpress-2026/https://modpagespeed.com/blog/fix-lcp-wordpress-2026/How to fix LCP on WordPress: diagnose the hero, inline critical CSS at the server, convert JPEG to WebP, and verify in Search Console. Step-by-step, 2026.Wed, 08 Apr 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/mod-pagespeed-alternatives/https://modpagespeed.com/blog/mod-pagespeed-alternatives/Google mod_pagespeed and ngx_pagespeed are no longer actively developed. Two maintained successors — mod_pagespeed 1.15 and ModPageSpeed 2.0 — exist. Here is how to choose.Mon, 16 Mar 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/aspnet-core-middleware/https://modpagespeed.com/blog/aspnet-core-middleware/Run the ModPageSpeed 2.0 optimization pipeline as ASP.NET Core middleware via NuGet — image transcoding, critical CSS, and cache serving in two lines of C#, no nginx reverse proxy required.Thu, 12 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/migrating-from-1x/https://modpagespeed.com/blog/migrating-from-1x/Migrate from Google's mod_pagespeed 1.13.x or ngx_pagespeed to ModPageSpeed 2.0: directive mapping, Docker Compose setup, image-format checks, and a verification checklist.Tue, 10 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/critical-css-heuristics/https://modpagespeed.com/blog/critical-css-heuristics/How ModPageSpeed 2.0 extracts and inlines critical CSS two ways: static heuristics in under 5ms on every page, plus an optional headless-Chrome path for true above-the-fold rules at First Contentful Paint.Sun, 08 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/economics-of-image-optimization/https://modpagespeed.com/blog/economics-of-image-optimization/Image CDNs run $35–$3,500/mo as traffic grows; self-hosted ModPageSpeed stays flat. Break-even is ~300–500K requests/mo. Full 2026 cost model, no bandwidth fees.Sat, 07 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/save-data-bandwidth/https://modpagespeed.com/blog/save-data-bandwidth/How ModPageSpeed 2.0 reads the Save-Data request header to serve lighter image variants -- a 30-50% bandwidth cut stacked on top of format and viewport optimization.Fri, 06 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/benchmarking-real-numbers/https://modpagespeed.com/blog/benchmarking-real-numbers/Measured ModPageSpeed 2.0 results on e-commerce, blog, news, and portfolio sites: WebP/AVIF image savings and real LCP, FCP, CLS, and Lighthouse gains on 3G, 4G, and broadband.Thu, 05 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/viewport-aware-image-optimization/https://modpagespeed.com/blog/viewport-aware-image-optimization/Serve WebP and AVIF automatically on nginx, self-hosted. ModPageSpeed 2.0 decodes each image once and generates up to 37 responsive variants across format, viewport, and pixel density.Tue, 03 Feb 2026 00:00:00 GMTOtto van der Schaafhttps://modpagespeed.com/blog/why-i-rebuilt-mod-pagespeed/https://modpagespeed.com/blog/why-i-rebuilt-mod-pagespeed/The story behind ModPageSpeed 2.0 — why mod_pagespeed is no longer actively developed, what was kept from PSOL, and how a new architecture replaced the RewriteDriver.Sun, 01 Feb 2026 00:00:00 GMTOtto van der Schaaf