A beautiful website that loads slowly, cannot be used with a screen reader, never shows up in search, or confuses visitors about what to do next is not a good website. Good sites are judged by what visitors can accomplish, and how easily. This step in our building for the web learning path covers the qualities professionals measure.
If you are new to the topic, start with How Websites Work.
1. Speed
Visitors leave slow sites. Speed also affects how search engines rank pages. Google publishes a set of measurements called Core Web Vitals that capture how fast a page feels to real people:
- Largest Contentful Paint (LCP): how long until the main content, usually the biggest image or block of text, appears. Google's guidance treats 2.5 seconds or less as good.
- Interaction to Next Paint (INP): how quickly the page responds when you tap or click. Good is 200 milliseconds or less.
- Cumulative Layout Shift (CLS): how much the page jumps around while loading, such as a button moving just as you tap it. Good is a score of 0.1 or less.
Common causes of slow pages are oversized images, too much JavaScript, many third-party scripts (ads, trackers, chat widgets), and servers far from the visitor. Common fixes are compressing and correctly sizing images, loading only the code a page needs, and serving files from a content delivery network.
2. Accessibility
About one in six people worldwide lives with a significant disability, according to the World Health Organization. Many use assistive technology: screen readers that speak the page aloud, keyboard-only navigation, magnification, or voice control. An accessible site works for them too.
The international standard is the Web Content Accessibility Guidelines (WCAG). A few of its core ideas:
- Text alternatives. Images that carry meaning have a written description (alt text) that a screen reader can speak.
- Keyboard access. Everything you can do with a mouse, you can do with a keyboard, with a visible indicator of where you are.
- Sufficient contrast. Text stands out clearly from its background.
- Clear structure. Headings, labels, and links describe their purpose, so people can navigate by them.
- No information by color alone. "Required fields are in red" fails for people who cannot see red.
Accessibility is also a legal requirement for many organizations, and it tends to make sites better for everyone: captions help in noisy places, clear labels help everyone fill in forms.
3. Being found: search and AI answers
A site nobody finds cannot help anybody. Search engine optimization (SEO) is the practice of making pages easy for search engines to understand and worth ranking. The foundations are not tricks:
- Each page has a clear purpose, a descriptive title, and a short summary (meta description).
- Content answers real questions thoroughly and accurately.
- Pages are fast, mobile-friendly, and linked logically from other pages on the site.
- Structured data, a standard vocabulary added to the page's code, tells search engines precisely what the page is: an article, a product, an event, a business.
People increasingly ask AI assistants instead of searching. Being cited in those answers, sometimes called generative engine optimization (GEO), rests on the same foundations: clear, accurate, well-structured content from a source that is easy to identify and verify.
4. Works on every screen
Most web traffic comes from phones. A responsive site rearranges itself for each screen size: navigation that collapses into a menu, text that stays readable without zooming, buttons large enough to tap, and nothing that spills off the side of the screen.
5. Security and trust
Visitors share personal and payment information only with sites they trust. Basics include HTTPS on every page, keeping software and plugins updated, collecting only the data the site needs, and a clear privacy policy. Trust also comes from content: real contact details, honest claims, and no surprises at checkout.
6. Clear content and a clear next step
Visitors arrive with a goal: learn something, compare options, buy, book, or get help. A good site makes the answer and the next step obvious. Plain language beats jargon. One clear call to action beats five competing ones. Every page should answer three questions within seconds: where am I, what can I do here, and what should I do next?
These qualities are measurable
Each quality above can be checked with tools and tests, not just opinions. Free tools such as Google's Lighthouse and PageSpeed Insights measure speed and flag basic accessibility and SEO problems. Accessibility checkers catch missing alt text and low contrast. Real users, including people who use assistive technology, catch what tools miss.
Try it yourself
Pick a website you use and evaluate it:
- Run it through PageSpeed Insights (search for it; it is free) and note the three Core Web Vitals.
- Try to use the whole page with only the Tab and Enter keys. Can you reach every link and button? Can you always see where you are?
- Open it on a phone. Does anything spill off the screen or require zooming?
- Ask a friend to find one specific piece of information on the site and time how long it takes.
The next step in this path turns these qualities into a testing checklist.
Look up any unfamiliar term in our glossary.