The best AI for web design is the one whose page you would actually ship, and the only way to know that is to look at pages. So here are four, built from one brief by Claude Opus 5.5, Claude Fable 5.1, GPT-6 Astra and GPT-6.1 Sol, with nothing changed afterwards. If you want the one-line version: the Claude pages look designed, the GPT pages look assembled well, and the gap between those two things is the whole decision.
What did the brief ask for?
A full marketing site, not a hero mockup. The prompt describes Driftwood, a booking link that protects a freelancer's focus time, and asks for a hero, testimonials, a feature section, pricing with a working monthly-to-yearly toggle, an FAQ and a footer, all in one HTML file. The copy facts and prices are fixed, so no model could win by inventing a better product. The full prompt is on the brief page, and the rules every model ran under are on the methodology page.
What did each model design?
Four different answers to the same sentence, and two of them are nearly the same answer.
- Claude Opus 5.5 built a working booking widget into the hero, with a calendar, time slots and a floating "focus guard" card, under the headline "Easy to book. Hard to interrupt." in a green-and-cream palette. It took 43 minutes and a 132 KB file.
- Claude Fable 5.1 centred one large serif headline, "Get booked without giving up your best hours", over a quieter gradient, with the product shot beneath. 28 minutes, 92 KB.
- GPT-6 Astra chose a terracotta accent, the headline "Less busy. More in flow.", a weekly calendar illustration and a row of integration logos. 10 minutes, 64 KB.
- GPT-6.1 Sol chose the same accent, the headline "Less busy. More you.", a near-identical calendar and the same logo row. 9 minutes, 73 KB.
That last pair is the most useful fact on this page. Ask the two GPT models for a landing page and you get one concept twice; ask the two Claude models and you get two concepts.
How long did each one take, and what did it cost?
Minutes versus tens of minutes, and the slower models also cost more per build. The table shows wall time, output tokens, file count and size, runtime errors and attempts for every build; none of it is a score.
| Model | Finished | Wall time | Output tokens | Files | Source size | Runtime errors | API-equivalent cost | Attempts |
|---|---|---|---|---|---|---|---|---|
| Claude Opus 5.5 | Yes | 43m 20s | 144k | 1 | 132 KB | 0 | $7.15 | 1 |
| Claude Fable 5.1 | Yes | 28m 14s | 131k | 1 | 92 KB | 0 | $10.88 | 1 |
| GPT-6 Astra | Yes | 9m 58s | 34k | 1 | 64 KB | 0 | $2.88 | 1 |
| GPT-6.1 Sol | Yes | 9m 08s | 45k | 1 | 73 KB | 0 | $0.69 | 1 |
Per million output tokens, Opus 5.5 lists at $20 and Fable 5.1 at $50 on Anthropic's pricing table, GPT-6 Astra at $50 and GPT-6.1 Sol at $10 on OpenAI's announcement. Counting every input and output token at those list prices, Sol's page cost $0.69 to make and Fable's $10.88, the figures in the cost column above. Whether Sol's page is a sixteenth as good is for you to say.
So which should you use for web design?
Use Claude Opus 5.5 when the page has to carry a brand and you can wait the better part of an hour; use GPT-6.1 Sol when you need a clean page in ten minutes and will tune the personality yourself. Fable 5.1 is the pick when you want restraint rather than density, and Astra is the one I would pass over here, because Sol gave the same design for a fifth of the price. That is one brief and one attempt each, so treat it as evidence, not a verdict.
Four landing pages, labels off. Pick the one you would put your name on, then reveal who built it.
Take the blind testHow do you check a web design build properly?
Three things, in order. Switch each build to the phone recording and watch whether the hero and the pricing cards reflow. Open the live build and click the yearly toggle: it should change every price, not just the headline one. Then open an FAQ item and scroll to the footer, because that is where a rushed build lets the template show. The dashboard brief, built from the same kind of fixed content, is the next page to watch once you have an opinion on this one: it shows whether a model's taste survives a denser interface.
Frequently asked questions
Which AI is best for web design right now?
On this brief, the two Claude models produced the more distinctive pages and the two GPT models produced the faster, tidier, more generic ones. Which of those is "best" depends on whether you want a brand or a template, so watch the four builds above and decide with the blind test rather than on our say-so.
Were these pages edited or touched up before publishing?
No. Each model got one attempt, 150 minutes at most, and the file it left on disk is what you see. The recordings are made with the same script for every build, scrolling at the same speed and using the same controls.
What did the brief ask for?
A complete marketing site for a fictional scheduling app called Driftwood, with a hero, testimonials, features, pricing that switches between monthly and yearly, an FAQ and a footer, as a single HTML file with fonts from Google Fonts and no other network requests.
Does the best AI for web design also handle the phone layout?
Not automatically. Every build was recorded on a 390 by 844 phone viewport as well as on desktop, and that recording is the quickest way to see whether a page reflows or simply shrinks. Use the Phone switch above the four videos to see it.