Verifies out that clever and conservative tuning over time bests the excesses created by many minds. No surprise there.
McMaster-Carr is a common ‘poster boy’ for speedy website performance. Domain registered in Aug 1994 and among the oldest, mcmaster.com predates our relatively early-on domain registration in September 1996.
I emailed the mcmaster tech / sales probably at least 15 years ago, complimenting the noticeably excellent performance and suggesting their tech people are likely underpaid, certainly under-recognized. It has taken many years and incredibly widespread, awful bloat and morass amongst too many websites and technologies for enough people to finally begin to realize and appreciate the necessity of speedy website performance – probably the glamor of ‘high-techiness’ aged poorly as the public honeymoon stage turned into actual business and life-use cases…and waiting around to be “dazzled” by yet more of anything not purpose-, goal- and results-driven staled badly. Aside from uptime reliability, speed is likely the second most critical factor in a website, with content third, approachable/usable UI design fourth, and all the rest a far ‘distant whatever’. Our tech design goals have always been reliability, speed, content, and general ‘goodness to purpose’ that serves and draws. A look back on archive.org at the decades of websites we’ve run shows this is not an empty claim.
Here is a good delve into what and how mcmaster exudes speediness.
Great question. The McMaster-Carr website is often cited as a kind of “poster child” for extremely fast web performance (despite using relatively old/“legacy” stacks). There’s no single magic trick; rather, a layered set of mature, well-executed optimizations. Below is a breakdown of many of the techniques (and trade-offs) involved, with how they relate to things like preloading, DNS, caching, JavaScript, YUI, etc.
What we do know about McMaster-Carr’s approach
First, let’s summarize what has been observed or reverse-engineered (or claimed) about McMaster-Carr’s performance setup. Many blog posts, dev articles, and even a public deconstruction (video) have attempted to reverse engineer it. (DEV Community)
Here are the core observed strategies:
| Technique | What McMaster is reported to use | What benefit it provides |
|---|---|---|
| Server-Side Rendering (SSR) / pre-rendered HTML | Most of their pages are rendered fully on the server (ASP.NET) rather than relying on heavy client-side rendering. (DEV Community) | Eliminates the delay of “waiting for JS to fetch or render content.” The browser can display HTML immediately. |
| Prefetch / predictive navigation / link-hover preloading | When a user hovers over a link, McMaster allegedly prefetches the HTML of the target page in the background so that subsequent click is nearly instantaneous. (DEV Community) | Reduces the latency of navigation, because much of the next page is already loaded. |
| Aggressive caching + CDN / edge caching | They cache static and semi-static content in a CDN (reportedly Akamai) and also use “Squid Cache” in the backend. (qrry.com) | Minimizes repeated work and serves content from geographically close nodes. |
| Service workers / client-side caching | There are reports they use service workers to intercept requests and serve from local cache, speeding up repeat visits. (DEV Community) | Once loaded, the browser can reuse resources without full network trips. |
| Preloading / resource hints | They preload critical assets (fonts, images) and use DNS prefetch / preconnect hints to resolve domains early. (DEV Community) | Moves asset fetching earlier in the page load to reduce stalls or rendering delays. |
| Critical CSS / inlining | The “above-the-fold” CSS required for initial rendering is inlined in the HTML; non-critical CSS is deferred. (qrry.com) | The browser can render the visual layout immediately without waiting on CSS downloads. |
| Minimal / page-specific JavaScript, legacy libraries (YUI, jQuery) | Rather than a massive JS framework, they use lighter, well-understood libraries (YUI, jQuery) and only load scripts that are strictly necessary for a given page. (DEV Community) | Reduces parsing, execution time, and the “blocking” cost of JavaScript. |
| Fixed image dimensions, sprites, image optimizations | Images have fixed widths/heights to prevent layout shifts; small images are combined into sprites to reduce HTTP requests. (qrry.com) | Prevents visual jank and lowers resource request count. |
| Performance measurement / monitoring | They instrument performance (e.g. performance.mark, etc.) to discover bottlenecks and continuously optimize. (qrry.com) | Enables feedback loops and ensures performance regressions are caught early. |
From those techniques, you can already see how things like preloading, DNS hints, caching, minimal JS, etc., all play a role.
Deeper dive: how the specific techniques (preload, DNS, JS, caching) fit together
To understand how McMaster’s speed is assembled, it helps to see how the various “layers” of optimization interact. Below is a conceptual stacking of techniques in typical high-performance web apps, and how McMaster (or any site aiming for ultra speed) might position each layer.
1. DNS prefetch / preconnect / resource hints
DNS Prefetch (rel="dns-prefetch")
This hint tells the browser: “Hey, start resolving this domain’s DNS now, even before any resource from it is requested.” Resolving DNS can take tens to hundreds of milliseconds depending on network. By doing it early (while the browser is parsing HTML), you hide part of that latency. (MDN Web Docs)
Preconnect (rel="preconnect")
This goes one step further: not only perform DNS resolution, but also establish the TCP handshake (and TLS handshake, if HTTPS). This is useful for domains you know you’ll need very early (e.g. your CDN, a font server). Preconnect is more aggressive, so it should be used cautiously (too many preconnects can compete for the browser’s limited connection slots). (MDN Web Docs)
Preload / Preload hints (rel="preload")
This explicitly tells the browser: “This resource is critical; fetch it now.” You can preload fonts, images, or scripts that you know will be needed immediately. Preload outranks many normal resource discovery heuristics, so it ensures the resource is fetched as soon as possible. (DEV Community)
Prefetch (rel="prefetch")
Prefetch is used for more speculative loading of resources you might need in the near future (e.g. the HTML, CSS, or images of the next page). It runs at a lower priority, so it doesn’t compete with the critical path. That’s exactly what McMaster is rumored to do when hovering over links. (DEV Community)
These resource hint techniques are additive — they let you push some of the waiting time earlier (while the browser is parsing) or sneak in speculative loads.
2. Caching (multi-layer)
Caching is central. You want to avoid repeated work at all levels: network, server, and client.
CDN + edge caching
Deploying a CDN ensures that assets (HTML, CSS, JS, images) are stored in a globally distributed network and served from nodes close to the user, reducing latency and backbone hops. McMaster is reported to use Akamai (or similar) for distributing many of its static and semi-static assets. (DEV Community)
Proxy / reverse proxy / cache layer (e.g. Squid Cache)
On the server side, a caching tier (such as Squid or Varnish or a custom proxy) can cache dynamic or semi-dynamic responses so that repeated requests can be served without re-invoking the full application logic. McMaster is reported to use Squid Cache. (qrry.com)
Browser cache + Cache-Control / immutable / stale-while-revalidate
Set HTTP headers like Cache-Control: max-age, immutable, or stale-while-revalidate to tell browsers when they can reuse cached resources without revalidating, or even when they may reuse stale copies while fetching newer ones in the background. (Frontend Masters)
Service worker / client-side cache
Using a service worker gives you more control: intercept outgoing requests and serve from a cache, decide when to refresh, or preload future navigations. If done carefully, it can make repeat visits nearly instant. McMaster is reported to use service workers to accelerate repeat traffic. (DEV Community)
The result is that for users who revisit or navigate around, many assets or even pages are already in local cache, dramatically reducing network round trips.
3. Render-path optimization: critical CSS, minimal blocking assets
To make the page appear and become usable quickly, you must optimize the “render path” — the parts of the page that block rendering or delay interactivity.
Critical CSS inlining
Extract the CSS required to render “above the fold” content and inline it in the HTML. This means the browser can lay out and paint visible content immediately without waiting for external CSS files. McMaster is believed to use this. (DEV Community)
Deferring or asynchronously loading non-critical CSS / JS
Non-essential styles or scripts can be loaded later (via defer, async, or dynamically via JS) so they don’t block the initial rendering.
Load only what’s needed (code splitting / page-specific scripts)
Instead of bundling all JS for the entire site on every page, load only the scripts needed for the current page (and perhaps lazily load others). McMaster’s site is reported to follow this pattern. (DEV Community)
Avoid layout shifts / reserve space
By specifying explicit widths, heights, or using placeholders, the layout doesn’t shift as assets (like images) load. McMaster uses fixed dimensions on images to avoid jank. (qrry.com)
Image optimizations / sprites
Combine small images into sprites (reducing number of requests), use optimized compression, and serve images with appropriate resolutions. McMaster reportedly uses sprites for UI icons, etc. (DEV Community)
4. Predictive navigation / prefetching (anticipating user actions)
One of the more “flashy” moves is prefetching HTML for future pages based on user behavior (e.g. link hover). This means much of the next page’s content is already fetched before the user even clicks, so when they do, there’s very little network latency left. McMaster is perhaps the most famous example of using this technique. (DEV Community)
That technique must be carefully engineered: you don’t want to over-prefetch (waste bandwidth) or prefetch too early (evict other useful cache entries).
5. JavaScript strategy: legacy libraries, minimalism, selective loading
Though McMaster uses “older” JS libraries like YUI (Yahoo! User Interface Library) and jQuery, they do so in a strategic, lean way. (DEV Community)
Key points in their JS strategy:
- Don’t bundle too much: Only include the code needed for that page; avoid “kitchen sink” frameworks that carry everything everywhere.
- Deferred / async loading: Non-critical JS is loaded later so it doesn’t block initial rendering.
- Progressive enhancement: The base HTML/UX works first; JS adds enhancements but is not required to see content (to the extent possible).
- Lean code and minimal dependencies: YUI/jQuery are relatively lightweight compared to heavy modern frameworks; also mature and well-understood, so optimization is easier.
- DOM diff / patch replacement instead of full re-render: Instead of client-side UI frameworks repainting the entire DOM, McMaster likely does incremental updates (replace a portion of the DOM rather than full re-render) when interacting. Observers suggest their navigation does “DOM replacement” of the new page content rather than full page reload. (Reddit)
By keeping JavaScript lean, parsing and execution overhead is minimized, and the “time to interactive” is very fast.
6. Monitoring, feedback loops, and continuous tuning
To maintain performance, developers must continuously measure and refine. McMaster is said to use performance.mark and browser APIs to instrument critical page phases, record latencies, and identify regressions. (qrry.com)
Metrics like “time to first paint,” “time to interactive,” “render latency,” “cache hit rates,” etc., all help guide incremental improvements.
Potential challenges, trade-offs, and caveats
While McMaster’s speed is impressive, the techniques are not trivial to get right. Here are trade-offs and pitfalls to watch out for:
- Prefetching overuse / bandwidth waste
If you prefetch too aggressively (especially on mobile or limited networks), you may fetch pages that the user never visits, wasting data and interfering with higher priority requests. - Cache invalidation complexity
When content changes (e.g. product stock, pricing, dynamic data), you need robust invalidation strategies so stale pages aren’t shown incorrectly. - Overhead of managing many layers
Multiple caching tiers, service workers, proxy caches, CDN, and link hints all add complexity. Mistakes (e.g. conflicting headers, stale caches) can be subtle and hard to debug. - Scalability of server-rendered dynamic content
If every user request triggers heavy database or business logic, SSR can become a bottleneck. You need aggressive backend caching, query optimization, and possibly sharding. - Browser heuristics / hint support
Not all browsers support all resource hints (preload, prefetch, preconnect) uniformly. You must design fallbacks. - Code complexity / testing cost
Because performance is a first-class concern, changes to UI or JS must be accompanied by tests to ensure you don’t regress performance. - Edge cases and “cold” visits
For first-time visitors (cache cold start), many of the benefits are reduced. But with effective prefetch, inlined critical CSS, and DNS hints, you still mitigate much of the cold-start cost.
Summary: how these techniques interplay to make a site “feel instantaneous”
Putting it all together, here’s how McMaster (or any site aiming for top-tier speed) makes the user experience feel instantaneous:
- The first page renders quickly because the server sends fully formed HTML and essential CSS is inlined.
- DNS hints and preconnects reduce the waiting for external domain resolution or TLS handshake.
- Critical assets (fonts, images, essential scripts) are preloaded so that as soon as the HTML renders, the browser already has the resources it needs.
- The JS layer is light — only what’s needed — so parsing and execution don’t block interactivity.
- For navigation, predictive prefetching (on hover or in background) ensures that much of the next page is already loaded before the user clicks.
- Caching at multiple levels (CDN, proxy, browser, service worker) ensures that repeated visits or navigations are served with minimal overhead.
- Continuous instrumentation ensures performance remains a priority and degradations get caught.
The result: even though they may use “older” stacks (ASP.NET, YUI, jQuery), their engineering discipline, layering of standard performance optimizations, and constant tuning let McMaster’s site outperform many modern-heavy JS sites.
Considering that mcmaster uses the ‘ancient’ YUI javascript, ‘well-aging’ smart design came to mind:
The very beginning of the World Wide Web has a clear “first site” and “first domain” story — but they’re not the same thing. Let’s separate them:
1. The first website ever
- Website: The very first website was hosted at
http://info.cern.ch/. - Date: It went online in August 1991.
- Creator: Tim Berners-Lee, at CERN in Switzerland.
- Content: It described the World Wide Web project itself — instructions on how to set up a web server, create web pages, and use a browser.
- Status today: The original pages have been reconstructed and are still available at http://info.cern.ch.
This was not only the first site, but also the first web server running on Berners-Lee’s NeXT computer.
2. The earliest registered domains
Domains predate the Web, since they were used for email, FTP, and other pre-web services. Domain Name System (DNS) was launched in 1983–1985, and the first domains were registered in March 1985:
- Symbolics.com — Registered March 15, 1985, by Symbolics Inc. (a computer manufacturer).
- This is the oldest domain name still in existence.
- It predates the Web itself (since Berners-Lee hadn’t invented HTTP/HTML yet).
- Other very early domains:
BBN.com(April 1985) – Bolt Beranek and Newman, ARPANET pioneers.Think.com(May 1985) – Thinking Machines Corporation.MCC.com,DEC.com,Northrop.com,Xerox.com,HP.com(1985).
So if your question is about the earliest domain ever registered, that’s Symbolics.com. If it’s about the first website, that’s info.cern.ch.
3. Who was first on the Web?
- Tim Berners-Lee is the undisputed first person on the Web, since he both built the software (the first browser/editor, called WorldWideWeb) and hosted the first server at CERN.
- The first group of users beyond him were CERN colleagues who accessed the early CERN HTTP servers.
- The first public invitation to join the Web was posted on the Usenet newsgroup alt.hypertext on August 6, 1991, when Berners-Lee announced the project. That date is often marked as the “public birth of the Web.”
✅ Summary:
- First website:
info.cern.ch(1991, Tim Berners-Lee, CERN). - First domain:
symbolics.com(1985, Symbolics Inc). - First user: Tim Berners-Lee himself, followed by CERN colleagues.