Science & Math APIs

Searches over 300 million metadata records and 40 million full text open access papers from thousands of repositories. A free API key raises limits above the unregistered tier.

Returns species occurrence records from museums, herbaria and citizen science projects worldwide, covering billions of georeferenced records. No key is needed for read access.

Unifies astronomy data from multiple observatories and catalogs behind one REST and OpenAPI interface, plus a pip installable command line client for scripting lookups of celestial objects.

Lists Indian Space Research Organisation spacecraft, launch vehicles, customer satellites and centres. This is a community built open source project, not an official ISRO service, and needs no key.

Gives machine readable access to crystal structures, phase diagrams and material properties. Browsing the web interface is free, but full API access starts near 9500 euros a year for academia.

Searches millions of digitized natural history specimen records and images contributed by museum collections. Built as a wrapper around Elasticsearch, free with no key for reads.

Evaluates math expressions such as factoring, simplifying, deriving and integrating by sending the expression in the URL path and returning a JSON result. Free to use with no key required.

Novelty API that tells you whether a submitted number is even. The free tier handles numbers up to 999,999 and injects joke ads, while paid plans from 1.99 dollars a month remove them.

NoctuaSky API returns night sky data including celestial bodies, constellations and upcoming events like meteor showers. The docs instruct clients to authenticate with an API key.

Searches astrophysics publications, citations and metadata from the NASA Astrophysics Data System. Authentication uses a personal API token, with a shared limit of 5000 requests per day.

Database of rocket launches, agencies, astronauts and launch pads worldwide. Free unauthenticated access is capped at 15 requests per hour, with higher limits available to Patreon supporters.

Reads and manages research projects, files and preregistrations on the OSF platform. Public data needs no key, though OSF Projects write endpoints close permanently in February 2027.

Looks up scientific names, synonyms and taxonomic hierarchy for plants and animals from the Integrated Taxonomic Information System. Offered as SOAP and REST services, no key needed.

Searches and retrieves metadata for research papers in physics, math and computer science, returned as Atom feeds. Free with no key, but limit yourself to one request every 3 seconds.

Reports the live location of the International Space Station and lists astronauts currently in space. It is a hobby project served over plain HTTP only, with best effort uptime and no key required.

Returns sunrise, sunset, twilight and moon phase times for any latitude and longitude. Free with no signup or key, though heavy callers should request a full year at once to avoid throttling.

Single portal covering NASA imagery, Mars rover photos and near Earth asteroids. Signup is instant and free, with the shared DEMO_KEY capped at 30 requests per hour against 1000 for a personal key.

Serves two line element orbital data for satellites, updated daily from CelesTrak and searchable by name or number. Free with no key, CORS enabled, with near perfect reported uptime.

Returns real time air quality readings from a crowdsourced network of PurpleAir sensors worldwide. Requires a free developer API key tied to a Google account to request data.

Delivers real time and historical earthquake event data filterable by time, location, magnitude and depth. Free with no key, returns up to 20,000 results per query in GeoJSON, CSV, KML or QuakeML.

Public REST API for SpaceX launches, rockets, capsules and crew history. The GitHub repository was archived in June 2026, but the hosted API still answers requests and needs no key.

Provides streamflow, gage height and water quality readings from over 1.5 million USGS monitoring sites. Standard use needs no key, with optional keys for higher rate limits.

Queries country, indicator and aggregate development statistics such as GDP, poverty and education across 189 member countries. Free with no key, available as JSON, XML or SDMX.

Read only search over high energy physics literature, authors, institutions and conferences, returned as JSON. No key needed, but each IP is limited to 15 requests per 5 second window.

Checks number properties like primality and perfect squares, converts numeral systems, and spells numbers as words. There is no free tier, plans start at 4.99 dollars a month for 5000 requests a day.