Map data
OpenStreetMap for the whole world. Every building and every address are kept in Europe, the United States, Canada and Mexico. Elsewhere a building or an address is kept only when it is also something else the API keeps, such as a shop, a café or a church.
Objects are kept when they carry one of these keys: aerialway, amenity, craft, drinking_water, highway, historic, landuse, leisure, man_made, mountain_pass, natural, office, piste:type, place, service:bicycle:repair, shop, sport, tourism, water, waterway, wetland. Administrative boundaries, protected areas and hiking, cycling, running and ski route relations are kept too.
Everything else is not in the data, even where OpenStreetMap has it: for example railway lines and stations, power lines, barriers and gates, bus stops tagged only with public_transport, military areas and telecom masts. Editing metadata (versions, users, changesets) is not included either.
Each region is loaded from a fresh Geofabrik extract and refreshed from time to time; edits made in OpenStreetMap after that show up with the next refresh. The date of the data is in osm3s.timestamp_osm_base of every Overpass answer.
Search by name
Finds cities, towns, villages, suburbs, hamlets and named localities, in the language you ask for where the map has the name. It does not find streets, addresses or places such as shops, stations or sights.
Overpass queries
The common Overpass QL scripts work as shown on Overpass QL examples; recursion (>, <) and queries without a bbox, around, poly, area or id do not. A query stops after 30 seconds. An area query over a large city for a common tag can reach that limit; a bbox, or several smaller areas, answer faster.
open_at keeps the places open at a local time by reading their opening_hours tag. Places without the tag, or with one that cannot be read, are left out and counted; holidays are not taken into account.
Weather
Hourly forecasts for up to 14 days anywhere. Over Europe the first days come from DWD ICON-EU at about 7 km, over the United States from NOAA HRRR and NBM at 2.5 to 3 km, and over Canada and the northern US from ECCC HRDPS and RDPS; elsewhere, and after those models end, from NOAA GFS at 0.11° and ECMWF IFS at 0.25°.
There is no weather history in the API, only forecasts.
Air quality and pollen
Air quality forecasts cover the whole world; pollen covers Europe only, and elsewhere its values are null. Measured values come from Sensor.Community citizen sensors, Syngeos sensors in Poland and official stations in Albania, Andorra, Austria, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czechia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Luxembourg, Malta, Montenegro, the Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Sweden, Switzerland and the United Kingdom. Other countries, Spain and Lithuania among them, have no official stations with current readings in the API. Most official stations report through the European Environment Agency, whose readings arrive two to six hours after they are measured; GIOŚ (Poland) and ČHMÚ (Czechia) report within the hour.
River levels
Gauges in Germany (federal waterways and North Rhine-Westphalia), France, England, Scotland, the Netherlands, Flanders, Luxembourg, Czechia, Ireland, Switzerland, Sweden, Finland, the United States and Canada. In Spain only Catalonia and part of the Guadalquivir basin have gauges; the rest of Spain (the Ebro, Tagus, Douro, Júcar, Segura and Guadiana basins, the northern basins, Galicia, the Basque Country, Navarre and Andalusia's Mediterranean coast) has none. In Italy only Lombardy, Veneto, Emilia-Romagna and South Tyrol have gauges, and Lombardy's levels arrive about five hours late. Finland's gauges report daily values. Other countries, Poland among them, have no gauges in the API.
Heights and terrain tiles
Heights and terrain tiles cover all land: 256 px tiles to zoom 13, 512 px tiles to zoom 12.
Routes
Routing covers the whole world. A route search that would take longer than two minutes stops with status 504; when every routing thread stays busy for 20 seconds, the request gets status 503.
Not in the API
Address search and geocoding, base map tiles, styles and fonts, 3D building models, isochrones and weather history.