Knowledge and science
Encyclopedias, papers, science news and the time and sky anywhere on Earth. 5 resources; API, key, license and embedding quoted from each site's own pages, checked Oct 23, 2026.
Wikipedia
You can query, stream or download the whole of human knowledge as people keep writing it, and reuse it in commercial products if you credit and share alike.
LiveAPI, no keyDownloadCommercial: conditions
arXiv
Much new research, especially in AI and physics, shows up here first, and you can query or mirror all of its metadata freely.
API, no keyDownloadCommercial OK
timeanddate.com
It answers the deceptively hard questions of time: when DST flips in a given country, when the sun sets there, and which day is a holiday where.
LiveLicense unclear
ScienceDaily
It is a steady daily stream of new findings across every field, each story pointing back to the institution and the paper behind it.
Commercial: conditions
Wolfram|Alpha
It computes answers instead of searching for them, so you get step-by-step math and live figures from curated data.
LiveAPICommercial: conditions
Side by side
| Resource | API | Key | Data download | Commercial use | Embed |
|---|---|---|---|---|---|
| Wikipedia The free encyclopedia plus a family of public APIs (Action API, REST API, pageviews, live edit stream) and monthly full database dumps of every Wikimedia wiki. |
Official API · Free | No | Yes (xml, sql, json, zim) | Commercial use with conditions | Embedding with conditions |
| arXiv The open preprint server for physics, maths, computer science and other fields, with a free keyless query API, OAI-PMH metadata harvesting and full-text PDFs and sources in bulk on Amazon S3. |
Official API · Free | No | Yes (xml, pdf, tex) | Commercial use OK | Embedding unclear |
| timeanddate.com A reference site for world clocks, time zones, daylight saving dates, public holidays, and sun and moon times. |
API unclear | — | — | Commercial use unclear | Embedding unclear |
| ScienceDaily A science news site that rewrites press releases from universities, journals and research institutes into short stories, sorted into topics and offered as free RSS feeds. |
No official API | — | — | Commercial use with conditions | Embedding with conditions |
| Wolfram|Alpha A computational knowledge engine that answers math, science, unit and fact questions by computing them, with a family of APIs including one tuned for LLMs. |
Official API · Free tier | Yes | — | Commercial use with conditions | Embedding with conditions |