The Obolus API and MCP

I’ve been working on Obolus, a personal finance tool focused on international comparisons (tax, net salary, cost of living).

One thing kept bothering me:

Most salary comparisons across countries use gross numbers.

But gross salary is basically meaningless when you compare different tax systems.

So I built a tax engine that calculates net income across multiple countries.

And now I’ve opened it up as a public API.

What it does:

- Input: annual gross salary

- Output: net salary across multiple countries

- Supports 8 countries (DE, AT, US, CH, CA, AU, UK, IE)

Example:

Same €60k → very different outcomes depending on the country.

The API is intentionally small:

- taxcompare (multi-country comparison)

- berechne (detailed payroll calculation)

Also added:

- OpenAPI spec for classic integrations

- MCP endpoint for agent-based systems

Docs:

Check our Postman doc:

I’m especially curious:

Would you use something like this in your own apps or workflows?

Thinking about use cases like:

- relocation tools

- salary benchmarking

- global hiring comparisons

Happy to hear feedback.