December 2, 2025 Smashing Newsletter: Issue #536
This newsletter issue was sent out to 181,601 subscribers on Tuesday, December 2, 2025.
Editorial
Performance tooling! Web performance might seem daunting at first, yet there is no shortage of neat little helpers to help us all find bottlenecks and opportunities to boost it. This newsletter is just about that.
We’ll cover tools for HTTP header performance, TTFB testers, little helpers to track bottlenecks, and an image analysis tool — just a few helpful bookmarks to keep close when working on web perf-related issues.
Today’s newsletter issue is kindly powered by our dear friends at DebugBear, a useful performance tool to monitor and optimize performance, including Google CrUX Data and RUM. Heads up to Matt and the team for their hard work and kind support! 🧡
The Smashing team is always on the roll: there are still early-bird tickets to SmashingConf Antwerp 2026 🍫 left! Until then, we have online workshops to finish the year strong:
- Theming Design Systems Design
with Samantha Gordashko. Dec 1–15 - How To Measure UX And Design Impact UX
with Vitaly Friedman. Dec 1–12 - The New CSS Toolkit Dev
with Kevin Powell. Dec 3–17 - Figma Workflow Masterclass Design
with Christine Vallaure. Dec 10–16 - Jump to all workshops →
Thank you, dear friends, and off we go into the world of testing, documenting, and applying web accessibility!
— Vitaly
1. Testing TTFB Around The World
Time to First Byte (TTFB) measures how quickly visitors to your website receive a response from your server. And that varies, depending on where they are located in the world. To find out where your website is fast and where you need to improve, DebugBear’s TTFB Test tests TTFB from ten locations across the globe — from San Francisco to Tokyo, Helsinki to Sydney.
2. Useful WebPerf Snippets
Whether you need an overview of all resources that are blocking rendering or want to track all interactions as you click around a page, Joan León’s WebPerf Snippets are sure to come in handy. It’s a curated list of useful snippets for Core Web Vitals, interaction, and loading. You can paste them into the browser console or run them directly in Chrome DevTools.
3. HTTP Header Performance Analyzer
A misconfigured website header has a direct negative impact on a site’s performance. To help you ensure your server’s HTTP headers are optimized for speed, Arjen Karel created the HTTP Header Performance Analyzer. All you need to do is enter a URL, and the tool analyzes the header for caching, compression, protocol, and security optimizations.
4. Find And Fix Performance Issues
Does your site respect performance good practices? And are there any front-end problems that slow it down? Yellow Lab Tools makes it easy to find out. Created by Gaël Métais, the tool collects various metrics and statistics for a given URL, which are then categorized and transformed into scores. No worries, you’re not left alone with the detected issues: The tool also provides precise information on how to fix them.
5. Get Your <head> In Order
How you order elements in the <head> of your page can affect performance, and the Capo.js Chrome extension is a handy little helper for optimizing sort order. The script logs two info groups to the console: the actual order of the elements in the <head> and the optimal order. A color system makes it easy to spot any high-impact elements out of order at a glance.
6. Context-Aware Web Performance
A low battery, weak connection, or enabled data saver mode — wouldn’t it be cool if you could adapt the experience based on a user’s context? Obs.js makes it possible. It uses the Navigator and Battery APIs to get contextual information about your user’s connection strength, battery status, and device capability, so you can adapt delivery accordingly.
7. Image Analysis Tool
Optimizing images can significantly speed up page load time. If you want to explore how changes to image size, format, quality, and encoding affect your site’s performance, Cloudinary’s free Website Image Analysis Tool provides you with actionable insights. It analyzes the images on any given page and evaluates the optimization potential.
8. Upcoming Workshops and Conferences
That’s right! We run online workshops on frontend and design, be it accessibility, performance, or design patterns. In fact, we have a couple of workshops coming up soon, and we thought that, you know, you might want to join in as well.
As always, here’s a quick overview:
- How To Measure UX And Design Impact UX
with Vitaly Friedman. Dec 1–12 - The New CSS Toolkit Dev
with Kevin Powell. Dec 3–17 - Figma Workflow Masterclass Design
with Christine Vallaure. Dec 10–16 - Behavioral Design Workshop UX
with Susan and Guthrie Weinschenk. Jan 15– 29 - Deep Dive On Accessibility Testing Dev
with Manuel Matuzović. Jan 19 – Feb 2 - Design Patterns For AI Interfaces UX
with Vitaly Friedman. Jan 22 – Feb 26 - Designing For Complex UI Masterclass UX
with Vitaly Friedman. Mar 3–17 - AI Design Patterns + Measure UX UX
with Vitaly Friedman. Friendly UX bundles (30% off) - Jump to all workshops →
9. Meet Design System Culture, Our Upcoming Smashing Book 📚
We have exciting news! We’re so happy to announce that “Maturing Design Systems,” a Smashing book by Ben Callahan, will soon be joining the Smashing Library! Ben’s insights and advice are so powerful, and we can’t wait to share this book with you! Pre-orders will be available soon.
You can read an excerpt of Maturing Design Systems, in which he explores the anatomy of a design system, explains how culture shapes outcomes, and shares practical guidance for the challenges at each stage — from building v1 and growing healthy adoption to navigating “the teenage years” and ultimately running a stable, influential system.
Stay signed up to our Smashing newsletter and be one of the first to know when Maturing Design Systems is available for preorder. We can’t wait to share this book with you!
That’s All, Folks!
Thank you so much for reading and for your support in helping us keep the web dev and design community strong with our newsletter. See you next time!
This newsletter issue was written and edited by Geoff Graham (gg), Cosima Mielke (cm), Vitaly Friedman (vf), and Iris Lješnjanin (il).
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