The latest articles on DEV Community by Mykola Droviannykov (@mykola_droviannykov_d1d62). https://dev.to/mykola_droviannykov_d1d62 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4024479%2F4ee42c3a-82d6-458a-8b4a-b58ff0b45474.png https://dev.to/mykola_droviannykov_d1d62 en Mykola Droviannykov Fri, 10 Jul 2026 19:48:24 +0000 https://dev.to/mykola_droviannykov_d1d62/we-built-a-free-ai-face-shape-detector-with-claude-vision-and-vercel-46ea https://dev.to/mykola_droviannykov_d1d62/we-built-a-free-ai-face-shape-detector-with-claude-vision-and-vercel-46ea <p>At Epica Beauty we kept seeing the same question from users: "what face shape do I have?" People were measuring their faces with rulers and comparing themselves to celebrity photos. So we built a small tool that answers it from a single selfie: <a href="https://testmyface.com" rel="noopener noreferrer">testmyface.com</a>.</p> <p>The stack is deliberately boring. The site is static HTML on Vercel. When a user uploads a photo, a single serverless function sends it to Claude's vision API with a prompt that asks for facial proportions (forehead width, cheekbone prominence, jawline shape, length-to-width ratio) and a classification into one of six shapes: oval, round, square, heart, diamond, or oblong. The response comes back as JSON with a confidence score and styling suggestions, and the frontend renders it. One page, one function, about $0.003 per analysis.</p> <p>Photos are never written to disk. The image goes from the browser to the function to the API and the result comes back in a few seconds.</p> <p>Things that surprised us: getting the model to commit to one shape instead of hedging between two took more prompt iteration than anything else, and a cheap small model classified faces as reliably as the larger ones once the prompt was strict enough.</p> <p>It is free and has no signup. If you try it, I would love to hear whether the classification matches what you thought your face shape was.</p> aiwebdevshowdevvercel