Facts API

The FactFusion AI Facts API gives you our verified facts as JSON. It is free, read-only and needs no key. Every fact comes with its sources, their tier, the editor's confidence score and the date it was verified.

Base address:

https://factfusionai.com/wp-json/factfusion/v1

Try it: https://factfusionai.com/wp-json/factfusion/v1/random?category=space

Endpoints

All endpoints use GET. Category is a category slug such as space, ocean or animal (see /categories).

Endpoint	Options	Returns
/facts	page, per_page (1 to 50, default 20), category, include (list of IDs)	Verified facts, newest first. The total is in the X-WP-Total and X-WP-TotalPages headers.
/facts/{id}	None	One fact, with its full explanation.
/random	category, exclude (an ID)	One random fact, with its explanation.
/search	q (at least 2 characters), limit (1 to 20)	Facts that match the words, with ID, title, claim and link.
/categories	None	Every category with its fact count and page.
/fact-of-the-day	None	Today's Fact of the Day. The same fact all day.

What a fact looks like

{
  "id": 189,
  "number": 189,
  "title": "A day on Venus is longer than its year",
  "slug": "a-day-on-venus-is-longer-than-its-year",
  "url": "https://factfusionai.com/fact/a-day-on-venus-is-longer-than-its-year/",
  "claim": "…",
  "short_answer": "…",
  "category": { "slug": "space", "name": "Space", "icon": "…" },
  "sources": [ { "name": "NASA", "title": "…", "url": "https://…", "tier": "A" } ],
  "confidence": 90,
  "verified_date": "2026-10-13",
  "verified_by": "…",
  "ai_assisted": true,
  "embed_url": "…",
  "explanation": "<p>…</p>"
}

Lists leave out explanation. ai_assisted is true when AI helped draft the wording; an editor still checked the fact against its source. Only published, verified facts are ever returned.

Example

fetch('https://factfusionai.com/wp-json/factfusion/v1/random?category=space')
  .then(r => r.json())
  .then(fact => console.log(fact.title, fact.sources[0].url));

The API answers requests from any website (CORS), so you can call it from a browser.

Limits and terms

• Up to 100 fact requests and 600 searches an hour from one IP address. Over the limit you get HTTP 429 with a Retry-After header.
• Need every fact? Download the open dataset instead of paging through the API.
• The facts are licensed CC BY 4.0. Show the fact’s source and link to the fact’s url on our site.
• The API may change. Breaking changes will get a new version (/factfusion/v2) and a note on our change log.