Mister Blocks

Key facts: Mister Blocks launched on Product Hunt on November 10, 2026, built by a dad for his son. Snap your loose bricks, spread flat on white paper, and it finds every piece, even the hidden ones, then designs four new models that really hold together, with 3D step-by-step instructions you can turn, zoom and print. Or describe any build in Prompt mode, a car, a robot, a character, and it researches it and designs it in real pieces in about 3 to 6 minutes. Every guide is stud-checked, and guides you have opened work offline. It runs on Claude Opus 5.5. It is an unofficial fan project: LEGO is a trademark of the LEGO Group, which does not sponsor it.

Plans: Free. There is no paid plan: every build is free, with a per-visitor daily limit and a site-wide daily budget, because each build costs a few dollars of API calls.

Best for: Families with a box of mixed LEGO and no instructions left. Who should skip it: anyone who only builds sealed sets by the official book, or who wants a licensed LEGO product.

Pros

• Completely free, with 3D instructions you can print
• Designs from the bricks you actually have, not a wish list
• Every build is stud-checked so it holds together in real plastic
• Guides you have opened work offline

Watch out for

• A per-visitor daily limit, because each build costs a few dollars of API
• It is an unofficial fan project, not a licensed LEGO product
• A photo needs pieces flat on white paper, studs up, not touching

Best for

Families with a box of mixed LEGO and no instructions left. Who should skip it: anyone who only builds sealed sets by the official book, or someone who wants a licensed LEGO product.

Pricing

Free. No paid plan: a per-visitor daily limit and a site-wide daily budget cover the API cost.

FAQs

What is Mister Blocks? A free LEGO AI: photograph your loose bricks and it designs four builds from the pieces you actually have, with stud-checked 3D step-by-step instructions.

Is Mister Blocks free? Yes. Every build is free, with a per-visitor daily limit, because each build costs a few dollars of API calls.

Can I ask for any build? Yes. In Prompt mode, describe a car, a robot, a character or a building and it designs it in real pieces in about 3 to 6 minutes.

Is it an official LEGO product? No. It is an unofficial fan project. LEGO is a trademark of the LEGO Group, which does not sponsor it.