topics#

GET /api/v1/topics Public — no key

List of curated topics — stable conceptual identifiers (e.g. star-wars, world-war-ii) with all aliases that map to them in the dataset, plus question counts. No API key required. Cached for 1h server-side, with Cache-Control: public, s-maxage=3600.

Counts freshness: question counts are pre-aggregated and refreshed when the dataset changes. Refresh cadence is irregular at launch — focus is on dataset quality and new languages, not a fixed import schedule. Once that pipeline lands we’ll publish the schedule.

Use this for typeahead search, dropdown filters, or as the first step of any “give me questions about X” flow.

Parameters#

Parameter	Type	Default	Description
lang	enum	en	Display language for `label`. Supported: `en`, `pl`. Other values return `400`.
q	string	—	Substring search across label, slug, and aliases (case-insensitive, 1–64 chars).
kind	enum	—	`tag` or `subcategory`. Limits results to one taxonomy layer.
cursor	string	—	Slug of the last item from the previous page. Use `_links.next` to navigate.
limit	int	100	Page size, 1–500.

Examples#

Response#

{
  "data": [
    {
      "slug": "biography",
      "kind": "subcategory",
      "label": "Biography",
      "aliases": [
        "biography",
        "biographical-facts",
        "biographies",
        "biographical-data",
        "biographical-details",
        "celebrity-biography"
      ],
      "count": 64977
    },
    {
      "slug": "american-history",
      "kind": "subcategory",
      "label": "American History",
      "aliases": [
        "american-history",
        "united-states-history",
        "us-history"
      ],
      "count": 19449
    }
  ],
  "meta": {
    "count": 2,
    "total": 2184,
    "language": "en",
    "requestId": "req_..."
  },
  "_links": {
    "next": "/api/v1/topics?lang=en&limit=2&cursor=..."
  }
}

Performance#

p50 (warm): ~23ms
p95: ~28ms (sustained 50 RPS, baseline)
Last measured: 2026-05-07
SLO: p95 < 500ms, error rate < 1%
Backed by pre-aggregated topic counts + 1h response cache.