Performance

Guides, how-tos, and updates on Performance.

14 articles

Core Web Vitals Explained: LCP, CLS, INP (and how to keep them green)
Performance

Core Web Vitals Explained: LCP, CLS, INP (and how to keep them green)

Google grades your pages on three numbers — and they affect both how your site feels and how it ranks. Here's what LCP, CLS and INP actually measure, what 'good' looks like, and how to fix them.

WatchFor Team
4 min read
Latency & Percentiles: why p99 matters more than the average
Performance

Latency & Percentiles: why p99 matters more than the average

Your average response time looks great — so why are users complaining? Because averages lie. Here's why percentiles like p95 and p99 tell the real story of how your service feels.

WatchFor Team
3 min read
What is a CDN? (And do you actually need one?)
Performance

What is a CDN? (And do you actually need one?)

A CDN makes your site faster by serving it from locations close to your users. Here's how that works, what you actually gain, and whether your site needs one.

WatchFor Team
3 min read
What is TTFB (Time to First Byte) and how to improve it
Performance

What is TTFB (Time to First Byte) and how to improve it

TTFB is the first number that tells you whether your backend is fast or slow. Here's what Time to First Byte measures, what's 'good', what makes it bad, and how to bring it down.

WatchFor Team
3 min read
ERR_TOO_MANY_REDIRECTS: causes and how to fix it
Performance

ERR_TOO_MANY_REDIRECTS: causes and how to fix it

When a page keeps redirecting to itself, the browser gives up with 'too many redirects'. Here's why redirect loops happen and the usual culprits behind them.

WatchFor Team
3 min read
How to Speed Up Your Website (the high-impact wins first)
Performance

How to Speed Up Your Website (the high-impact wins first)

Website speed affects conversions, bounce rate and even SEO. The good news: most of the gains come from a short list of fixes. Here they are, roughly in order of impact.

WatchFor Team
3 min read
LCP Explained: Largest Contentful Paint (and how to improve it)
Performance

LCP Explained: Largest Contentful Paint (and how to improve it)

LCP is the Core Web Vital that answers 'when does the page feel loaded?' Here's exactly what it measures, what counts as good, and the handful of fixes that move it most.

WatchFor Team
3 min read
CLS Explained: Cumulative Layout Shift (and how to fix it)
Performance

CLS Explained: Cumulative Layout Shift (and how to fix it)

CLS measures the most annoying thing on the web: the page jumping around as it loads. Here's what it is, what counts as good, and how to stop your layout from dancing.

WatchFor Team
3 min read
INP Explained: Interaction to Next Paint (and how to improve it)
Performance

INP Explained: Interaction to Next Paint (and how to improve it)

INP is the newest Core Web Vital — it measures how quickly your page responds when people actually interact with it. Here's what it is, what's good, and how to make your site feel snappy.

WatchFor Team
3 min read
Lighthouse Explained: how to read the score
Performance

Lighthouse Explained: how to read the score

Lighthouse gives your page a 0–100 score across performance, accessibility, SEO and more. Here's what it actually measures, how to read it, and the trap of chasing a perfect 100.

WatchFor Team
3 min read
Image Optimization for the Web (the biggest easy win)
Performance

Image Optimization for the Web (the biggest easy win)

Images are usually the heaviest thing on a page — and the easiest to fix. Here's how to make them load fast without looking worse: compress, resize, modern formats, and lazy loading.

WatchFor Team
3 min read
Caching Explained: browser, CDN and server caches
Performance

Caching Explained: browser, CDN and server caches

Caching is the closest thing the web has to free speed: store a result once, reuse it many times. Here are the three layers of caching, how each works, and the one hard part — invalidation.

WatchFor Team
3 min read
Gzip vs Brotli: web compression compared
Performance

Gzip vs Brotli: web compression compared

Text compression shrinks your HTML, CSS and JS before they travel — for free speed. Here's how gzip and Brotli compare, and which to use where.

WatchFor Team
3 min read
Web Font Performance: fast text without the flash
Performance

Web Font Performance: fast text without the flash

Custom fonts make a site look great — and can quietly slow it down or make text vanish during load. Here's how to keep your typography both beautiful and fast.

WatchFor Team
3 min read