Open API library
Every public API in one place
Stratum gathers free, well documented APIs from governments, research labs and the open web. Browse, inspect and visualize what they return.
25 sources across 20 categories.
What you will find
Hundreds of curated sources
Each entry is reviewed for availability, license and response shape.
Adaptive viewers
JSON trees, tables, maps and charts adapt to the data returned.
Open and free
Only APIs that work without payment, with clear quotas and terms.
Browse by category
Open data8General purpose open datasets, country and statistics services.Weather2Forecasts, current conditions and climate observations.Finance5Currencies, market data, macroeconomic indicators.Crypto2Cryptocurrency prices and blockchain explorers.Geo and maps4Geocoding, routing, tiles and geographic data.Government3Public sector datasets and civic APIs.Science4Scientific datasets, research feeds and reference data.Space2Astronomy, launches, satellites and planetary data.AI and ML1Free model inference, datasets and language tools.Images and media2Photo libraries, illustrations, avatars and visuals.Words and language1Dictionaries, thesauri, translation and linguistic services.Sports1Scores, fixtures, athletes and team data.Transport1Transit feeds, flights, vehicles and mobility data.Food1Food products, nutrition data and recipes.Health1Public health, medical references and wellness data.Realtime2Streaming APIs and live event feeds.Social1Public social platforms and community data.Entertainment6Movies, TV, games, music and pop culture.Security0Vulnerabilities, threat intelligence and breach data.Blockchain1Block explorers, smart contracts and on chain data.