İş Hesaplama: labor-law calculators that show their source

The problem

Turkish workers search for overtime, notice-period and annual-leave math, and find calculators that give a number with no reason to trust it.

What I built

Five free calculators: overtime, weekly working hours, notice period, annual leave and a monthly timesheet, plus explainer articles. Each tool prints the law article it implements and the date it was last checked. When the law or a parameter changes, that date changes with it.

Key decisions

• Trust is a component. A required legal-basis line sits on every tool page, so no calculator can ship without naming its source.
• No third-party requests. Fonts are self-hosted. Analytics run on my own Umami server behind the site’s own domain, so the visitor’s browser never calls an outside service and no cookie banner is needed.
• Turkish type that never breaks. İ and ı live in different font subsets; if one drops, headings show empty boxes. A build script checks that every character in real product strings has a glyph, and a development-only page lets me check them by eye.
• Ads never split the form from the result. It is written into the product rules, not left to taste.
• Accessible contrast. The original orange accent failed WCAG AA on white for text; it was replaced by a darker token, and the decision is recorded so it doesn’t come back.
• Moved without losing search traffic. The calculators started on msclabs.tr and moved to their own domain; every old URL has a 301 redirect, tracked in a redirect map.

Proof

• The overtime logic is covered by 15 unit tests.
• Type checks and tests run in CI on every push.
• The site builds to static HTML served by nginx.