Open data API and MCP server
Everything on this page is free, needs no key and is licensed CC BY 4.0. Use it in apps, research or AI assistants and credit obrotomierz.pl with a link to the dataset. There is no personal data anywhere here: only the open datasets that are also published on Zenodo with a DOI.
MCP server for AI assistants
The Model Context Protocol lets an AI assistant query a data source directly instead of guessing. Our server is read-only, needs no sign-in and answers from the same files as the website:
https://obrotomierz.pl/mcp Transport: Streamable HTTP (protocol versions 2024-11-05 to 2025-11-25), one JSON response per request. Tools:
| Tool | What it returns |
|---|---|
| get_polish_savings_bonds_offer | Polish retail treasury savings bonds (obligacje oszczędnościowe Skarbu Państwa: OTS, ROR, DOR, TOS, COI, EDO, ROS, ROD) currently on sale: series code, term, first-period interest rate, inflation margin and early redemption fee, from the official issue letters of the Polish Ministry of Finance. |
| get_polish_savings_bond_series | Details of one Polish retail treasury savings bond series by its code (for example EDO1136 or COI1130): terms, margin, early redemption fee and the interest rate in every interest period that has started. |
| get_retail_government_bonds_by_country | Whether a country sells government bonds to individuals at issue and how they pay (inflation plus a fixed margin, market real rate, fixed, floating, step-up or prize), for all 195 countries, with the official source for each. Without a country: the number of countries in each category and the countries paying inflation plus a fixed margin. |
| get_eu_bank_account_opening_bonuses | Banks in the 27 EU countries that pay a cash bonus for opening a personal current account, read one by one from bank websites, with the amount, deadline and source page. With a country code: every bank paying a bonus there. Without it: the number of banks with a bonus in each country. |
How to connect
Claude Code:
claude mcp add --transport http obrotomierz https://obrotomierz.pl/mcp Claude on the web and in the desktop app: Settings, Connectors, Add custom connector, then paste the address above. Any other client that supports remote MCP servers over Streamable HTTP works the same way: add the address, no token needed.
Files
The same data as plain files. Addresses without a date always hold the latest version; dated copies never change.
Polish retail treasury savings bonds, 1999 to today
- https://obrotomierz.pl/dane/obligacje/emisje.csv
- https://obrotomierz.pl/dane/obligacje/oprocentowanie.csv
- https://obrotomierz.pl/dane/obligacje/apka.json
Updated monthly, after the new issue letters · DOI 10.5281/zenodo.23208023
Government savings bonds for individuals in 195 countries
- https://obrotomierz.pl/dane/obligacje-na-swiecie/panstwa.csv
- https://obrotomierz.pl/dane/obligacje-na-swiecie/produkty.csv
- https://obrotomierz.pl/dane/obligacje-na-swiecie/marze.csv
Updated with each new version · DOI 10.5281/zenodo.23638786
Fair use and corrections
The files change at most once a day, so cache them. The numbers come from official sources (issue letters of the Polish Ministry of Finance, government debt agencies, bank websites), and each dataset page explains its method and limits. Bank bonuses change often: the binding terms are always on the bank page. Found an error? Write to me. obrotomierz.pl shows data and does not give financial advice.