Developer API

Query the knowledge graph

A read-only JSON API over the same verified, evidence-backed data that powers the public pages. No key required for fair use. Every value is traceable to stored evidence; responses serve published entities only.

Conventions

Base URL: http://officialcost.com
All responses are JSON over HTTPS. Published (discovery + verified) data only.
Fair-use rate limits per IP: search 30/min, graph 60/min. Over-limit returns 429 with Retry-After.
Responses are CDN-cached (search ~60s, graph ~5min) — expect Cache-Control headers.
Please attribute OfficialCost and link back when republishing values.

Endpoints

GET/api/search?q={query}&type={type?}

Ranked entity search. Optional type filter: country | city | occupation | university | visa.

http://officialcost.com/api/search?q=berlin&type=city

{
  "query": "berlin",
  "results": [
    { "slug": "berlin", "name": "Berlin", "type": "city",
      "isoCode": null, "status": "verified", "path": "/city/berlin" }
  ]
}

GET/api/graph/entities?type={type?}&limit={1-500}

List published entities with their scores, ordered by importance.

http://officialcost.com/api/graph/entities?type=country&limit=100

{
  "count": 100,
  "entities": [
    { "slug": "germany", "name": "Germany", "type": "country",
      "publicationStatus": "verified", "coverage": "82.00",
      "kds": "91.0", "confidence": "88.00", "importance": "95.00",
      "factCount": 41, "relationshipCount": 12 }
  ]
}

GET/api/graph/entities/{slug}

Full node for one entity: scores, verified facts, relationships, and contributing sources.

http://officialcost.com/api/graph/entities/germany

GET/api/graph/entities/{slug}/history

Fact version history (the time series behind trend charts).

http://officialcost.com/api/graph/entities/germany/history

{
  "slug": "germany", "count": 7,
  "versions": [
    { "attribute": "vat_rate_standard_pct", "version": "3",
      "value": "19", "confidence": "90.00",
      "changeType": "verified", "createdAt": "2026-05-01T00:00:00Z" }
  ]
}

Feeds & discovery

/sitemap.xml — full URL index
/feed.xml — RSS of the latest verified updates

This API is provided for general guidance only and is not financial, legal, or relocation advice. Endpoints and response shapes may evolve; breaking changes will be announced.

http://officialcost.com/api/search?q=berlin&type=city { "query": "berlin", "results": [ { "slug": "berlin", "name": "Berlin", "type": "city", "isoCode": null, "status": "verified", "path": "/city/berlin" } ] }

http://officialcost.com/api/graph/entities?type=country&limit=100 { "count": 100, "entities": [ { "slug": "germany", "name": "Germany", "type": "country", "publicationStatus": "verified", "coverage": "82.00", "kds": "91.0", "confidence": "88.00", "importance": "95.00", "factCount": 41, "relationshipCount": 12 } ] }

http://officialcost.com/api/graph/entities/germany/history { "slug": "germany", "count": 7, "versions": [ { "attribute": "vat_rate_standard_pct", "version": "3", "value": "19", "confidence": "90.00", "changeType": "verified", "createdAt": "2026-05-01T00:00:00Z" } ] }