A tax engine for 15 countries where every figure cites a dated source

Relocation and hiring decisions get made on headline income-tax rates. Those hide employer contributions, VAT and duties on everyday spending, property and wealth taxes, and the health care, childcare or schooling you pay for privately where the state doesn’t. Most calculators also add VAT on top of the price instead of finding it inside the price, which overstates it.

What a headline rate shows

Income taxhidden from the comparison

What TotalTax adds up

Income taxSocial contributionsEmployer contributionsVAT & duties on spendingProperty & wealthCover you buy privately

• Income tax
• Social contributions
• Employer contributions
• VAT & duties on spending
• Property & wealth
• Cover you buy privately

The engine is a pure TypeScript package with zero dependencies. Each country is a data pack, so adding a market is a data change, not a rewrite. Before any jurisdiction ships, a research dossier collects its rules from official sources, and the build checks that every number the engine can emit points back to one of them.

1. Step 1 (input): Published sources, official, dated.
2. Step 2 (ai agent): Research dossier, 16 so far.
3. Step 3 (human gate): Dossier reviewed, complete or not at all.
4. Step 4 (automated): Data pack, a market is data.
5. Step 5 (automated): Source gate, every figure dated. Rejected here: Unsourced figure (build fails).
6. Step 6 (automated): Invariant tests, ~1,100 tests. Rejected here: Earn more, keep less (test fails).
7. Step 7 (live): In your browser, nothing sent.

1. agent://researcher

   Writes a research dossier per jurisdiction from official, published sources, with a date on every figure.

   Never allowed to: use a figure it can’t source.

2. human://vegardHUMAN GATE

   Reviews each dossier. A jurisdiction ships complete, or it doesn’t ship.

3. agent://architect

   Split the product into a zero-dependency engine, data packs and the web app, so a new country is a data change.

4. agent://builder

   Implements the income models per country: employee, sole trader, company owner and retired.

5. agent://fact-checker

   Runs the source gate: the build fails if any figure the engine can show lacks a dated, published source.

   Never allowed to: let an unsourced number ship.

6. agent://tester

   Runs ~1,100 tests, including sweeps that prove earning more never leaves you with less, and invariants that make the books balance.

7. human://vegardHUMAN GATE

   Wrote the rules for sponsored options: never the default, priced at the top of the advertiser’s range, and tested so a sponsor can’t win every case.

TotalTax is static files plus a tiny Worker that sets strict security headers. The calculation runs on the visitor’s own device, so ten visitors or ten thousand cost about the same: close to nothing. There is no database and no user data, which also means nothing to breach.

• The engineA pure package with zero dependencies, reusable in your site, app or API.
• The data packs and their sourcesEvery figure with its source and date, in your repository.
• The research protocolHow a new market is researched, reviewed and shipped.
• The test suiteConformance, invariants and money logic, run on every change.
• The web appShareable result links, lead capture where you want it.
• Your Cloudflare accountHosting and security headers, under your name.