I built a free printable coloring pages website for kids, powered by AI generation.
The Fun Part:
Almost all the code was generated by Windsurf with Claude Sonnet 4.5. This was an interesting experiment - I never thought I could actually pull this off. It's fascinating to see what's possible with AI-assisted development today.
Background:
As a parent, I noticed my kids love coloring, but most online resources are either low quality or require paid subscriptions. So I built this using AI to provide high-quality coloring pages for free to all parents.
Core Features:
- AI-generated high-quality line art (powered by Google Gemini)
- 50+ themed categories (animals, holidays, nature, etc.)
- Age-appropriate content (3-12 years) with difficulty levels
- One-click PDF download, print-ready
- Multi-language support (English, Chinese, etc.)
- User favorites and browsing history
Tech Stack:
- Next.js 16 + React 19
- Drizzle ORM + PostgreSQL
- MeiliSearch for search
- Cloudflare R2 for image storage
- Google Gemini AI for content and category generation
- Tailwind CSS + shadcn/ui
Interesting Challenges:
1. AI category consistency - Built a "memory system" to make AI reuse existing categories instead of creating duplicates
2. Image optimization - Using Next.js Image optimization with preloading strategy, LCP < 1.5s
3. SEO - Implemented structured data and multilingual sitemaps, now indexed 500+ pages on Google
Future Plans:
- Custom AI generation from user prompts (text-to-coloring-page)
- Image upload to generate coloring pages (image-to-coloring-page)
- User upload and sharing features
Feel free to try it out and share your feedback! I'd especially love to hear suggestions on technical implementation and product direction.
The source code is not open-sourced yet, but happy to discuss technical details.
While I'm not one to suggest monetizing something that benefits a community I think you could reasonably monetize this by providing CaaS (ha! Coloring as a Service).
You could have weekly or monthly pdfs of generations emailed for particular themes like kids' school mascots, religious subjects like for Sunday school, curriculum subject correlating theme, etc.
Additionally, I would have it hide a signature somewhere in case someone starts scraping images and commercially selling them, or additionally license them to be able scrape them using Cloudflare.
I contemplated the same idea a while back because I'm constantly printing out colouring sheets for kids and it seemed like an app people would use.
Ultimately I decided not to build it because there are so many free colouring page sites out there, and there's a non-zero environmental cost to asking Gemini to generate a happy bat image.
Pretty much any colouring page a kid could ask you for is already a Google search away. In fact the challenge is not finding a happy bat colouring page but narrowing it down from the thousands of results.
I just don't see the value in using Gemini to add yet more generic colouring pages to the millions that exist. I'm sorry, I don't mean to poop on your work, it's interesting to read the tech implementation but ultimately I don't like creating walled gardens with AI generated alternatives to what's already free
Feature request - a way to filter by age / difficulty from the home page. I see it on individual pages but didn’t quickly see the age listed as a tag. This is a point of friction on most coloring page sites. Congrats on this. I have bookmarked it. Thank you
For others who stumble upon this, another good free site without too many ads:
8 comments
[ 4.7 ms ] story [ 32.2 ms ] threadI built a free printable coloring pages website for kids, powered by AI generation.
The Fun Part: Almost all the code was generated by Windsurf with Claude Sonnet 4.5. This was an interesting experiment - I never thought I could actually pull this off. It's fascinating to see what's possible with AI-assisted development today.
Background: As a parent, I noticed my kids love coloring, but most online resources are either low quality or require paid subscriptions. So I built this using AI to provide high-quality coloring pages for free to all parents.
Core Features: - AI-generated high-quality line art (powered by Google Gemini) - 50+ themed categories (animals, holidays, nature, etc.) - Age-appropriate content (3-12 years) with difficulty levels - One-click PDF download, print-ready - Multi-language support (English, Chinese, etc.) - User favorites and browsing history
Tech Stack: - Next.js 16 + React 19 - Drizzle ORM + PostgreSQL - MeiliSearch for search - Cloudflare R2 for image storage - Google Gemini AI for content and category generation - Tailwind CSS + shadcn/ui
Interesting Challenges: 1. AI category consistency - Built a "memory system" to make AI reuse existing categories instead of creating duplicates 2. Image optimization - Using Next.js Image optimization with preloading strategy, LCP < 1.5s 3. SEO - Implemented structured data and multilingual sitemaps, now indexed 500+ pages on Google
Future Plans: - Custom AI generation from user prompts (text-to-coloring-page) - Image upload to generate coloring pages (image-to-coloring-page) - User upload and sharing features
Feel free to try it out and share your feedback! I'd especially love to hear suggestions on technical implementation and product direction.
The source code is not open-sourced yet, but happy to discuss technical details.
While I'm not one to suggest monetizing something that benefits a community I think you could reasonably monetize this by providing CaaS (ha! Coloring as a Service).
You could have weekly or monthly pdfs of generations emailed for particular themes like kids' school mascots, religious subjects like for Sunday school, curriculum subject correlating theme, etc.
Additionally, I would have it hide a signature somewhere in case someone starts scraping images and commercially selling them, or additionally license them to be able scrape them using Cloudflare.
I am working on the categorisation as well now, is something difficult to do
Let me know if you need help with anything!
I contemplated the same idea a while back because I'm constantly printing out colouring sheets for kids and it seemed like an app people would use.
Ultimately I decided not to build it because there are so many free colouring page sites out there, and there's a non-zero environmental cost to asking Gemini to generate a happy bat image.
Pretty much any colouring page a kid could ask you for is already a Google search away. In fact the challenge is not finding a happy bat colouring page but narrowing it down from the thousands of results.
I just don't see the value in using Gemini to add yet more generic colouring pages to the millions that exist. I'm sorry, I don't mean to poop on your work, it's interesting to read the tech implementation but ultimately I don't like creating walled gardens with AI generated alternatives to what's already free
For others who stumble upon this, another good free site without too many ads:
https://colorango.com/