CAcardhedger
GemRate Population

Get Population Data by Certificate Number (GemRate Contract Required)

Changed on

Resolves a grader certificate to its card, then returns the full GemRate population report. Adds a cert block giving the queried slab's own grade and its position in the population.

This endpoint is available only to commercial customers with their own GemRate contract. GemRate population data is licensed, so Card Hedge cannot serve it to customers who do not hold a contract with GemRate directly.

Access requires an Enterprise-tier API key with GemRate access explicitly enabled on it. Every other request — including Enterprise keys that have not been enabled — receives a 403 Forbidden response. Contact support@cardhedger.com to have GemRate access enabled once your GemRate contract is in place.

Daily allowance of uncached lookups. The first time a certificate is looked up it needs a live call to our grading-data provider and draws on your account's daily allowance of such lookups; repeat lookups are served from cache and do not. See Rate limits in the API overview for your tier's allowance.

post/v1/cards/population-by-cert

Request

  • Base URL
    https://api.cardhedger.com
  • Auth
    API key in header X-API-Key

Request body

certstring required

Certificate number

graderstring

Grading company (defaults to PSA)

Example request

{
  "cert": "50000000",
  "grader": "PSA"
}

Response

Successful Response

gemrate_idstring required
universal_gemrate_idstring nullable
descriptionstring nullable
population_typestring nullable
as_ofstring nullable

GemRate report date

last_population_changestring nullable

Example response

{
  "as_of": "2026-08-04",
  "card": {
    "card_number": "344",
    "category": "baseball-cards",
    "parallel": "Base",
    "player": "C.C. Sabathia",
    "set_name": "Bowman Chrome",
    "year": "1999"
  },
  "description": "1999 Bowman Chrome C.C. Sabathia Base 344",
  "gemrate_id": "25783324b9710f1366ca4d54f3dd4689c02b6885",
  "graders": [
    {
      "gem_rate": 0.3705,
      "gems": 641,
      "grader": "PSA",
      "grades": [
        {
          "auto": 1,
          "count": 1,
          "grade": "PSA Authentic",
          "non_auto": 0,
          "qualifiers": 0
        },
        {
          "auto": 12,
          "count": 963,
          "grade": "PSA 9",
          "non_auto": 951,
          "qualifiers": 4
        },
        {
          "auto": 5,
          "count": 641,
          "grade": "PSA 10",
          "non_auto": 636,
          "qualifiers": 0
        }
      ],
      "set_url": "https://www.psacard.com/pop/baseball-cards/1999/bowman-chrome/34101",
      "specid": "378808",
      "total_population": 1730
    }
  ],
  "last_population_change": "2026-07-28",
  "population_type": "universal",
  "totals": {
    "gem_rate": 0.3836,
    "total_gems_or_greater": 906,
    "total_population": 2362
  },
  "universal_gemrate_id": "25783324b9710f1366ca4d54f3dd4689c02b6885"
}

Changes