slashyear - sourced history

Full-text search across every dated entry in the historical record, plus the subjects that match. Each entry is a sentence quoted verbatim from a numbered English Wikipedia revision and carries that revision id, so an answer built on it can cite a source that will still say the same thing next year. Use this whenever you need a dated fact.

{
  "type": "object",
  "properties": {
    "query": {
      "type": "string",
      "description": "words to find, e.g. 'volcanic eruption' or 'Constantinople'"
    },
    "from_year": {
      "type": "integer",
      "description": "earliest year; astronomical numbering, so -43 means 44 BCE"
    },
    "to_year": {
      "type": "integer",
      "description": "latest year"
    },
    "limit": {
      "type": "integer",
      "description": "maximum entries to return (default 25, max 200)"
    }
  },
  "required": [
    "query"
  ]
}

Everything the record holds for one year: the headline summary and every dated entry, grouped by subject, each with its source revision.

{
  "type": "object",
  "properties": {
    "year": {
      "type": "integer",
      "description": "astronomical numbering: 1969, or -43 for 44 BCE"
    }
  },
  "required": [
    "year"
  ]
}

One calendar day across every recorded year — what happened on 4 July in all of them. This aggregate exists in no single encyclopedia article.

{
  "type": "object",
  "properties": {
    "date": {
      "type": "string",
      "description": "'july-4', 'July 4', '07-04' or any 'YYYY-MM-DD'"
    }
  },
  "required": [
    "date"
  ]
}

One subject's whole record in date order: every dated entry across all years in which Wikipedia's editors linked to it, with its Wikidata id for joining to other datasets.

{
  "type": "object",
  "properties": {
    "subject": {
      "type": "string",
      "description": "subject name or slug, e.g. 'Byzantine Empire' or 'byzantine-empire'"
    },
    "from_year": {
      "type": "integer"
    },
    "to_year": {
      "type": "integer"
    },
    "limit": {
      "type": "integer",
      "description": "default 100, max 1000"
    }
  },
  "required": [
    "subject"
  ]
}

One country's dated record, century by century, harvested from the per-country year articles English Wikipedia writes separately ('1969 in Japan') and never indexes together. Use this when the question is about a nation rather than a year or a subject.

{
  "type": "object",
  "properties": {
    "country": {
      "type": "string",
      "description": "country name or slug, e.g. 'Japan', 'south-africa'"
    },
    "from_year": {
      "type": "integer",
      "description": "earliest year; astronomical numbering"
    },
    "to_year": {
      "type": "integer",
      "description": "latest year"
    },
    "limit": {
      "type": "integer",
      "description": "default 200, max 2000"
    }
  },
  "required": [
    "country"
  ]
}

What a year (1800-2025) looked like in numbers, from outside sources rather than encyclopedia prose: world population, U.S. CPI and what a dollar then is worth now, average U.S. prices (gas, eggs, bread, milk, houses, income, minimum wage), who led the major powers, and the Billboard Hot 100 No. 1 songs. Every figure carries its source. For any other country's leaders use get_leaders.

{
  "type": "object",
  "properties": {
    "year": {
      "type": "integer",
      "description": "1800 to 2025"
    }
  },
  "required": [
    "year"
  ]
}

Who led a country (or every country) in a year, 1800-2025: heads of state, heads of government and ruling-party leaders, in the order they held the post. Each name is quoted from Wikipedia's list of state leaders (revision id given) and kept only where the person's Wikidata record holds the same post over the same years, so a missing name means the sources disagree, not that the post was empty.

{
  "type": "object",
  "properties": {
    "year": {
      "type": "integer",
      "description": "1800 to 2025"
    },
    "country": {
      "type": "string",
      "description": "optional: country or state name, e.g. 'Brazil', 'Ottoman Empire', 'Soviet Union'. Omit for every state"
    }
  },
  "required": [
    "year"
  ]
}

The Billboard Hot 100 No. 1 single on a given date (1958-08-04 onward): the first chart issue dated on or after that day, quoted from a cited Wikipedia revision.

{
  "type": "object",
  "properties": {
    "date": {
      "type": "string",
      "description": "YYYY-MM-DD"
    }
  },
  "required": [
    "date"
  ]
}

Inflation-adjust U.S. dollars between years with the BLS CPI-U (1913 onward). Omit to_year for the latest published month.

{
  "type": "object",
  "properties": {
    "amount": {
      "type": "number"
    },
    "from_year": {
      "type": "integer"
    },
    "to_year": {
      "type": "integer",
      "description": "optional; default is the latest CPI month"
    }
  },
  "required": [
    "amount",
    "from_year"
  ]
}

The world on one date in a single answer: the dated entries for that exact day, births and deaths that day, every state's office holders that year, the Billboard Hot 100 No. 1 in force, U.S. prices and CPI, world population, official series (unemployment, rates, GDP, debt, CO2, temperature), Federal Reserve exchange rates for that day, and that year's Nobel Prizes. Each part carries its source; parts no source covers are absent.

{
  "type": "object",
  "properties": {
    "date": {
      "type": "string",
      "description": "YYYY-MM-DD, e.g. 1969-07-20"
    }
  },
  "required": [
    "date"
  ]
}

Check one dated sentence against the record before stating it. Leaders, Billboard No. 1 singles and Nobel Prizes get a structured check that can return 'supported' or 'contradicted' with the source. Other claims are matched against the dated entries and the answer says where the record dates sentences holding the claim's key words (matched_same_year, matched_other_years, ...), with the entries as evidence.

{
  "type": "object",
  "properties": {
    "claim": {
      "type": "string",
      "description": "e.g. 'Richard Nixon was president of the United States in 1975'"
    }
  },
  "required": [
    "claim"
  ]
}

Nobel laureates for a year (1901 on) or for a category across years, from the Nobel Prize API and kept only where Wikidata records the same prize in the same year.

{
  "type": "object",
  "properties": {
    "year": {
      "type": "integer"
    },
    "category": {
      "type": "string",
      "description": "Physics, Chemistry, Physiology or Medicine, Literature, Peace, Economic Sciences"
    },
    "name": {
      "type": "string",
      "description": "optional: laureate name to find"
    }
  }
}

Official data series by year from the agencies that publish them, each cross-checked against a second copy: U.S. unemployment, federal funds rate, GDP, population, federal debt, Mauna Loa CO2, global temperature anomaly, Fed exchange rates. Omit series to list them.

{
  "type": "object",
  "properties": {
    "series": {
      "type": "string",
      "description": "series id from the list, e.g. 'unemployment_rate'"
    },
    "from_year": {
      "type": "integer"
    },
    "to_year": {
      "type": "integer"
    }
  }
}

Where two sources slashyear checks against each other disagree: leaders' terms (Wikipedia lists vs Wikidata), birth and death dates (Wikipedia year articles vs Wikidata), Nobel Prizes (Nobel API vs Wikidata). Useful before trusting either source.

{
  "type": "object",
  "properties": {
    "person": {
      "type": "string",
      "description": "optional: name to look for"
    },
    "section": {
      "type": "string",
      "description": "optional: leaders, life_years, life_days or nobel"
    },
    "limit": {
      "type": "integer",
      "description": "default 50, max 500"
    }
  }
}

Browse the countries that have a record of their own, largest first.

{
  "type": "object",
  "properties": {
    "limit": {
      "type": "integer",
      "description": "default 100, max 500"
    }
  }
}

Browse the subjects that have a timeline, largest record first.

{
  "type": "object",
  "properties": {
    "starts_with": {
      "type": "string"
    },
    "limit": {
      "type": "integer",
      "description": "default 50, max 500"
    }
  }
}