Context
A calculator website has to be right every time: a single wrong result undermines trust in the whole site. And the rules change: Brazil's social security, income tax and small-business tax tables (INSS, IRRF, Simples Nacional and MEI) are updated every year.
Challenge
Keeping hundreds of calculation pages consistent, fast and up to date, without relying on manual page-by-page review.
Goal
Build a tools platform that scales in number of pages without losing accuracy, and that Google understands well.
Solution
A static website generated with Astro, where each calculator uses an isolated, tested calculation engine. Official tables are centralized, with the source of each value. Tool hubs and journeys organize navigation.
Architecture
- Astro 7 with TypeScript: static HTML, fast loading
- Data validation with Zod
- Site search with Pagefind, no search server
- Publishing via deploy script
Features
- Calculators and simulators across several areas (real estate, labor, dates, interest)
- Favorites
- Tool hubs and journeys by topic
- Analytics layer that doesn't send the data users type in
SEO
- Sitemap and canonical on every page
- Step-by-step structured data where it makes sense
- Monitoring through Google Search Console
Automation
- Publishing via script, with no manual file copying
Results
- Platform in production with about 378 URLs in the sitemap (Sep 2026)
- A structure that allows adding calculators without rewriting the site