Colorado Information Marketplace vs EPA

The Colorado Information Marketplace is the state's open-data portal, built on the Socrata platform and covering budget, transportation, public-safety, and demographic datasets from Colorado agencies. Every dataset is queryable through Socrata's SODA REST API without an account, with an optional free app token only needed to raise the anonymous rate limit. Results are returned as JSON by default, with CSV and XML also available per dataset.

EPA's Envirofacts platform exposes the agency's environmental compliance and monitoring databases — air quality, drinking water systems, the Toxics Release Inventory, hazardous waste, and Superfund sites — through a keyless REST API at `data.epa.gov/efservice`. Any of the underlying tables can be queried by building a URL from the table name, filter columns, and an output format, with results returned as JSON, XML, CSV, or Excel. EPA's Developer Central site separately documents smaller topic widgets built on the same data.