Census.gov

The US Census Bureau provides various APIs and data sets on demographics and businesses

Official docs outline

Extra Credit builds an outline of Census.gov's docs the first time your work uses it. Until then, start at the official documentation.

Boletín Oficial del Estado (BOE) Official Spanish State Gazette open data: laws, summaries and XML/JSON APIs
Brazil Community driven API for Brazil Public Data
Brazil Central Bank Open Data Brazil Central Bank Open Data
Brazil Receita WS Consult companies by CNPJ for Brazilian companies
Brazilian Chamber of Deputies Open Data Provides legislative information in Apis XML and JSON, as well as files in various formats
Bureau of Labor Statistics US labor statistics: inflation, unemployment, wages and productivity
City, Berlin Berlin(DE) City Open Data
City, Gdańsk Gdańsk (PL) City Open Data
City, Gdynia Gdynia (PL) City Open Data
City, Helsinki Helsinki(FI) City Open Data
City, Lviv Lviv(UA) City Open Data
City, Nantes Open Data Nantes(FR) City Open Data