Slop Check by NightMarquee

Slop Check by NightMarquee is a free diagnostic tool that answers one question: does your site look AI-made? You paste a website address, press the check button, and the tool opens that page in a real browser at two widths — 1280px for desktop and 390px for mobile — then scores it out of 100 and shows you what to change, all in about a minute. It is built for the people who now ship a large share of the web's pages: designers, developers, founders and anyone building sites with AI builders such as Lovable, Bolt, Cursor, Claude or Codex. Its purpose is to replace the vague feeling that a page looks templated with a specific, itemised verdict you can act on. The problem it addresses is convergence. Sites produced with AI builders tend to reach for the same visual habits, and after you have seen enough of them the result reads as generated at first glance even when the layout is functional. Slop Check names those habits and counts them. The pattern groups the detector looks for include overused fonts, glow on everything, springy busy motion and cards inside cards, alongside tiny text, low contrast and more. To show how widespread these habits are, the site publishes a report on how often the patterns show up on 705 YC homepages. Results land in three bands: 0 to 59 reads as AI-generated, 60 to 89 means some generic habits, and 90 to 100 is labelled slop-free. The first group of patterns is typography. The detector flags Inter, Instrument Serif, Space Grotesk and a handful of other faces as overused, together with italic serif accents in big headlines, a pill label sitting above every heading, and body text set smaller than 14px. The illustrated example contrasts a generic hero — a pill label, a sans headline with one italic serif word and small grey text — against a hero set in one distinctive serif with a 16px paragraph. The recommended fix is to pick a face with a point of view, keep headlines upright and set body text at 16px, which restores a sense of authorship that repeated defaults remove. The second group covers colour and glow. Purple-to-blue gradients, coloured glows behind buttons and gradient headline text are described as the default look of generated sites, and text placed on those treatments often fails contrast as well. The good example on the site replaces all of it with a near-black page, solid text and a single orange button. The fix the tool recommends is one accent colour, solid text and neutral shadows, which keeps attention on content instead of on effects. The third group is motion. Springy easing that overshoots and then settles, animated widths and heights, and marquees that never stop all make a page feel like a template, and the tool notes that they cost frames on phones. The fix is ease-out curves, animating only transform and opacity, and letting loops stop — changes that preserve a sense of life on the page without the busyness that signals a stock template. The fourth group is layout nesting: a grid of identical feature cards, each carrying an icon tile and a coloured side stripe, all wrapped inside one more card. Because every box competes for attention, nothing leads and the eye has no entry point. The tool's advice is fewer boxes, letting headings, spacing and order carry the hierarchy instead, as in its example of a headline beside a short numbered list with no boxes at all. The score itself is deliberately narrow. Only the 31 patterns that make a site look AI-made count toward the headline number, and every site starts at 100. Each pattern costs points once, no matter how many times it appears on the page: minus 15 for an error rule, minus 8 for a warning rule, minus 4 for a minor rule, and nothing at all for advisory notes. The remaining 29 checks — contrast, line length, spacing, broken scripts and other craft problems any site can have — are reported as their own design quality score so they never drag the headline down. Even a perfect result is framed honestly: 100 means none of the known generic patterns showed up, not that the site is well designed, because taste, content and how the thing works are still yours to judge. Under the hood the tool runs Impeccable, Paul Bakaus's open-source design detector, under an Apache-2.0 licence. The team states that it runs the detector unmodified, currently engine 0.1.22, and that the site is not affiliated with or endorsed by Impeccable. Every finding arrives with instructions for fixing it, and the fixes are also compiled into a single prompt that holds all of them at once, ready to paste into Lovable, Bolt, Cursor, Claude or Codex so an assistant can apply the corrections in one pass rather than one at a time. The output has a social layer as well. Ticking "Add my result to the public board" publishes a check to a board that lists public results best first, while leaving it unticked keeps the result reachable only by people with the link; result pages are kept out of search engines either way. Sites scoring 90 or more can copy a badge code from their result, paste it on their homepage and press "I pasted it". The badge displays the score while the homepage keeps it, and the homepage is rechecked every week. If a page is built only by a script and has no HTML to paste into, verification uses a small file instead. Site owners can verify with a small file or a meta tag to hide a result from the board for good, or take a badge instead — though a badge alone does not hide a site. Results for sites you do not own can be reported to support@nightmarquee.com for a person to review. What you come away with is a concrete to-do list rather than a critic's opinion. Instead of being told a page looks generic, you see which named patterns were found at desktop and mobile width, what each one costs you in points, and the specific change that clears it. That turns an aesthetic argument into a checklist you can work through, and the combined prompt means the fixes can be handed straight to an AI assistant instead of being translated into instructions by hand. Typical workflows follow from that. You can run a check on a page you just generated with an AI builder before you launch, then paste the combined prompt back into the builder to clean it up. You can benchmark a site against public results for well-known pages — notion.com and nightmarquee.com list at 100, linear.app and stripe.com at 92, framer.com at 84 — to see where you sit on the board. You can earn a badge once you cross 90 and show the score on your homepage, with weekly rechecking keeping it current. And you can skip the cleanup entirely by starting from a NightMarquee prompt: every prompt builds a site that passes this check, and all 84 demos in the library score 100 because each one is rechecked with the same detector on every change and nothing ships with a finding. Access is deliberately frictionless. Slop Check is free, with no account and no email required, runs on the web, and takes about a minute per check. Each person can run 5 checks an hour, and the same page is rechecked at most once an hour. You get one page checked — the one you enter — at both desktop and mobile width. Anything not covered by the on-site questions goes to support@nightmarquee.com. Slop Check by NightMarquee is best understood as a fast, free way to catch the design tells that make an AI-built site look like every other AI-built site, and to get a numbered, fixable list back in about a minute. It does not claim to judge taste; it claims to spot the known generic patterns, price them in points out of 100, and tell you how to remove them.