Querying the HTTP Archive and finding your Performance Plateau | PerformanceObserver In this episode, Paul Calvano dives deep into querying the HTTP Archive dataset to uncover web trends, while Tammy Everts breaks down the "Performance Plateau", explaining why identifying your specifi...

So excited to be paired with @paulcalvano.bsky.social for this double-header on PerformanceObserver next week!

Paul will take a deep dive into the HTTP Archive. Then I'll break down the "performance plateau" – why you need to know it and how to find it.

performanceobserver.dev/events/episo...

SpeedCurve | How fast is fast enough? Rethinking web performance in pragmagical terms Always remember: We're in the business of creating experiences for other humans.

In our rush to align page speed with SEO and business metrics, have we in the #webperf community lost our way? In this post, based on the keynote I gave at #PerfNow a few months ago, I explore how it's not too late to bridge the gap between pragmatism and user delight.

www.speedcurve.com/blog/fast/

SpeedCurve | 2025 was a big year! Here are some highlights... From broad browser support for key metrics to nuanced metrics for diagnosing issues, 2025 has been filled with wins.

ICYMI, here's a wrap-up of exciting #webperf and #ux highlights from 2025!

⭐ Broad browser support for LCP and INP (W👀T!)
⭐ New metrics & visuals for measuring user happiness
⭐ Deeper metrics for JS diagnostics
⭐ Better budgets = easier regression-fighting

www.speedcurve.com/blog/2025-we...

SpeedCurve | 2025 was a big year! Here are some highlights... From broad browser support for key metrics to nuanced metrics for diagnosing issues, 2025 has been filled with wins.

I ❤️ writing these annual wrap-up posts. From broad browser support for key metrics to nuanced metrics for diagnosing issues, 2025 has been filled with huge wins — not just for @speedcurve.com but for our entire #webperf community. Go, us!

www.speedcurve.com/blog/2025-we...

A time series chart that shows how a web performance budget works. This chart tracks Cumulative Layout Shift (CLS). Over time the metric fluctuates. The performance budget is represented as a red horizontal line across the chart, which is the predetermined ideal maximum threshold for the metric. When the CLS metric is greater than the budget, it's highlighted in red. When the metric improves and drops below the budget, it returns to normal.

If you only have time to do ONE THING to make your site holiday-ready (so you can relax and enjoy the next few days off) it's this: CREATE PERFORMANCE BUDGETS

😀 No code changes required
😀 Literally takes just 1-2 minutes
😀 You get alerts if your pages slow down

👉 www.speedcurve.com/web-performa...

Impact Brief: Embrace Acquires SpeedCurve, Advancing User-Focused Observability with Deep Web Performance Insight EMA explores how Embrace and SpeedCurve’s combined strengths create a comprehensive experience layer across mobile, web, and backend systems.

🚨 New EMA Impact Brief: Embrace + @speedcurve.com is a big step forward for modern #observability.

Together they deliver deeper user context, unified mobile + web + synthetic visibility, and an OTel-first foundation built for AI-ready reliability.

Read more ➔ ow.ly/tsXY50XxcpZ

What happens when observability merges with front-end performance monitoring? You get the best of all worlds — performance, reliability, and UX across web and mobile!

Join our founder @markzeman.com, CPO @cliffcrocker.bsky.social, and @embrace.io President Andrew Tunall on December 9 to learn more!

Pictorial graph that shows relative weight of images on web pages, according to the HTTP Archive. The median page has 1053 kilobytes worth of images, while the 75th percentile page has 2892 kilobytes and the 90th percentile page has 6888 kilobytes.

Unoptimized images are STILL a common problem, and they hurt things like:

🙁 #A11y
🙁 #webperf and #UX metrics like LCP and CLS
🙁 Conversions
🙁 #SEO
🙁 Sustainability

I'll be talking about this (and solutions!) today (12:15pm PT / 3:15pm ET) at #PixelPalooza.

Get your FREE ticket: lnkd.in/g_N8YFrs

Third-Party Web Performance | SpeedCurve Ads, analytics, and social widgets can seriously hurt page speed. Find out how to measure and optimize the third parties on your pages.

Third parties represent a MASSIVE potential single point of failure for your site.

1. AUDIT & remove unused tags

2. DEFER or load asynchronously

3. TRACK scripts & create #webperf budgets

4. KNOW your SLAs with vendors

5. CREATE a playbook for failures

👉 www.speedcurve.com/web-performa... #ux

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SpeedCurve | 2025 Holiday Readiness Checklist (Page Speed Edition!) 25 things you can do to keep your site fast and your users happy through the holidays and beyond!

🎄 Holiday Readiness Tip 7: Track your CDN!

CDN performance can be a black box. Did you know you can track CDN health using Server Timing headers?

👉 How to get backend transparency from your CDN: www.speedcurve.com/blog/server-...

👉 More holiday readiness tips: www.speedcurve.com/blog/holiday...

PixelPalooza 2025 PixelPalooza will explore all the best practices we, as developers, can leverage media like images, video, audio and documents across our sites and applications.

#PixelPalooza is coming up this Thursday!

This awesome FREE online event covers how to make sure all those helpful images and videos on your site don't hurt #webperf and #a11y.

I'm joining @seancdavis.com to talk about the hidden cost of media on the web.

Get your ticket 👉 cfe.dev/events/pixel...

How Fast Is Fast Enough? <p>It sounds like a simple question, but if you’ve been working in performance long enough, you know the answer is far from straightforward. In this Day 1 keynote, Tammy asks questions—from neuroscien...

Video of my @perfnow.nl keynote is up! In this talk, I challenged the false choice between magic and pragmatism.

Don't settle for "fast enough". Instead, aim to create a user experience that's #pragmagical — blending user delight with measurable business impact.

conffab.com/presentation...

Text on a dark blue background: SpeedCurve joins Embrace.

SpeedCurve has been acquired by @embrace.io! We’re combining forces to connect performance, reliability and UX across web and mobile apps.

And yes, our team and tools will remain the same. 😀

Our founder @markzeman.com shares how our 12-year journey led us here: www.speedcurve.com/blog/perform...

SpeedCurve | NEW! Heatmaps now available on Favorites Dashboards We’ve finally added heat maps to your Favorites (custom) dashboards — one of our most requested features ever! It feels great to finally make this available to everyone.

I love heatmaps so much! They're the best way to get instant insight into where #webperf issues are lurking across your site.

Taking it even further, you also get breakdowns across dimensions like page label, browser, device, and location. *chef's kiss*

👉 www.speedcurve.com/blog/new-hea...

How Fast Is Fast Enough? [PerfNow 2025] It sounds like a simple question, but if you've been working in web performance long enough, you know the answer is far from straightforward. In this ke&hellip;

Slides from my @perfnow.nl talk — How Fast Is Fast Enough? — are up!

If you’re at #PerfNow (or even if you’re not) I’d love to talk about creating a delightful experience for your users.

speakerdeck.com/tammyeverts/...

SpeedCurve | Correlation charts: Connect the dots between site speed and business success If you could measure the impact of site speed on your business, how valuable would that be for you?

Sharing a few of the sources I cited during my #PerfNow talk, I’ll start with this one…

Here’s a deeper dive into how to create correlation charts that help you see the relationship between performance metrics and business/engagement metrics.

www.speedcurve.com/blog/site-sp...

SpeedCurve | Why you need to know your site's performance plateau (and how to find it) Have you ever wondered why your site got faster, but your business and user engagement metrics didn't change? Here's why.

Another source from my #PerfNow talk…

Here’s why you need to know the performance plateau for your site.

www.speedcurve.com/blog/web-per...

SpeedCurve | The Definitive Guide to Long Animation Frames (LoAF) LoAF lets you identify problem scripts, quantify the impact of third-party scripts, and improve the user experience. Here's everything you need to know to get started.

For #PerfNow folks who want to go even deeper on Long Animation Frames, @andydavies.me wrote the definitive guide.

www.speedcurve.com/blog/guide-l...

SpeedCurve | NEW! Monitor Long Animation Frames and get to the bottom of your JavaScript issues Now you can monitor Long Animation Frames (LoAFs) and fix the third parties and other scripts that are hurting your user experience!

Learn more about Total Blocking Duration (TBD), the experimental new metric that @andydavies.me is pioneering. #PerfNow

www.speedcurve.com/blog/long-an...

Making Sense of LoAF by Andy Davies Over time the web has become more reliant on JavaScript… but we’ve very little information on how its growth is affecting our visitors’ experience.

Making Sense of Long Animation Frames…

The slides from my #PerfNow talk are available on Notist

noti.st/andydavies/9...

SpeedCurve | Does Interaction to Next Paint actually correlate to user behavior? If you make INP faster, will it actually improve the user experience... and help your business? Here's our analysis.

And last (but definitely not least) here’s @cliffcrocker.bsky.social’s super-interesting analysis of INP and its correlation with UX and business metrics. #PerfNow

www.speedcurve.com/blog/INP-use...

Text on a blue background: “SpeedCurve is a great tool — and 75% of the value we get is from our check-in sessions with their team! In our internal quarterly State of the Stack meetings, Speedcurve gets the most consistent accolades as a helpful resource. The platform, and the actual guidance from actual people, has enhanced our website and the knowledge of our team. The check-ins with Cliff are something special: on the calendars as optional for most of the team, yet everyone attends. Working with Speedcurve has allowed us to streamline our monitoring stacks because it is so comprehensive. We don’t need as many tools as we thought we did."

We ❤️ making users happy! One of our customers (a large healthcare system) had this to say about our tools and service — including kudos to our amazing @cliffcrocker.bsky.social!

👉 Learn how we collaborate with you to build your #webperf and #ux practice: www.speedcurve.com/why/collabor...

SpeedCurve | Are your retail landing pages killing conversions? How do the campaign landing pages of leading websites compare? Who's fast, who's slow, and what's causing their page speed bottlenecks?

Excessive JS is a UX monster. It hurts important metrics like LCP and INP, which in turn hurts bounce rate and conversion rate.

I dug into this topic in a recent post, where I compared the #webperf of landing pages for well-known sites, from Apple to Uber.

www.speedcurve.com/blog/campaig...

SpeedCurve | NEW! A smarter way to spot performance issues We’re excited to announce the launch of the Vitals Overview dashboard in SpeedCurve. It's your new starting point for exploring the performance of your site.

I've been exploring @speedcurve.com's new Vitals Overview dashboard with some customers for a week or so now, and all I can say is WOW.

Not only is it fun to play with, it also halves the time it takes to investigate #webperf and #ux issues.

👉 Take a quick tour: www.speedcurve.com/blog/a-smart...

😂

Yoda (from Star Wars, if that needs to be clarified) with the text "Patience you must have."

We just added @csswizardry.com to our Web Performance Heroes starter pack! (Yes, it's a bit late, but better late than never.)

Every month, we honour a new hero and add them to this list. Follow along and meet the folks without whom the web would be a sadder and slower place.

go.bsky.app/FTbRtFk

performance.now(); 30th and 31st of October, Amsterdam On 30th and 31st of October, 2025, the sixth edition of performance.now() will take place in Amsterdam—a single track conference, covering today’s most important web performance insights.

Every fall I hear so much FOMO from folks who missed @perfnow.nl. Don't let it happen to you!

We have amazing speakers sharing the newest best practices for the #webperf topics you care about: AI, APIs, #a11y, CSS, JS, frameworks, tools, culture, workflows & more!

Get your tickets soon! perfnow.nl

How fast is fast enough? I'll be exploring this question in my #PerfNow keynote. I hope to see you there! And if you have your own thoughts on this question, I'd love to hear them!

#webperf #sitespeed #pagespeed #ux