I built 217 free calculators in 12 languages — notes on multilingual SEO

I run Calnex (https://calnex.pro), a free calculator platform. 217 tools, 12 languages, ~7,000 URLs. Here's what's actually happening with SEO:

1. Programmatic pages get crawled but not indexed. Google crawls everything, then parks 4,000+ pages in "Crawled - currently not indexed." The fix isn't technical — it's convincing Google the pages deserve to exist.

2. Language versions multiply the problem. 12 languages × 600 tools = a lot of near-duplicate surface area. Hreflang and self-referencing canonicals are table stakes.

3. What actually earns indexing: pages with real substance — worked examples, explanations, internal links — get in. Thin template pages don't.

4. Validation takes weeks. Google's "validate fix" flow for thousands of URLs is measured in weeks, not days. Plan accordingly.

The site itself is free, no sign-up, no tracking. If you're doing programmatic/multilingual SEO, happy to compare notes.