Price & Population Data API

Prices: every grade, every grader, with the evidence

Not a formula. Each figure is the median of real completed sales at that exact grade and grading company, published only when there are three or more inside the window. Sale counts, window, newest sale and the change against the previous window ride along, so your model knows how much to trust each number.

GET https://www.pokeinvest.io/api/prices/pi_16322
X-API-Key: your_key

{
  "pokeinvest_id": "pi_16322",
  "name": "Gengar EX #108",
  "set_name": "Pokemon Fire Red & Leaf Green",
  "currency": "USD",
  "ungraded": { "median_usd": 949.5, "sales": 32, "window_days": 90,
                "newest_sale": { "usd": 1050.0, "date": "2026-09-25" }, ... },
  "graded": [
    { "grader": "PSA", "grade": "10", "median_usd": 26525.0, "sales": 4, "window_days": 365,
      "low_usd": 21000.0, "high_usd": 32000.0,
      "newest_sale": { "usd": 27500.0, "date": "2026-08-30" }, "change_vs_previous_window": null },
    { "grader": "PSA", "grade": "9",  "median_usd": 8700.0,  "sales": 16, "window_days": 90,
      "change_vs_previous_window": 0.58, ... },
    { "grader": "CGC", "grade": "Pristine 10", ... },
    { "grader": "BGS", "grade": "9.5", "median_usd": 6550.0, "sales": 20, ... }
  ],
  "estimates": { "note": "vendor figures, not measured by us", "psa_10": 26000.0, ... },
  "population": { "psa_total": 3300, "psa_10": 105, "cgc_total": 428, "psa_last_updated": "2026-09-20" }
}

• Measured, and labelled as such — anything under graded or ungraded came from sales we can show. Vendor figures live under estimates and never mix in.
• Tiers above 10 are separate — BGS Black Label, CGC Pristine 10 and a plain 10 are different prices, because they are.
• Recomputed every night from 547,000+ completed sales, behind a gate that refuses to publish a price that moved on thin evidence. 2,800+ cards carry measured prices today and the count grows nightly; the rest return estimates only.

Populations: the same key, the same IDs

GET https://www.pokeinvest.io/api/population/pi_46078
X-API-Key: your_key

{
  "pokeinvest_id": "pi_46078",
  "tcgplayer_id": "146698",
  "name": "Mewtwo GX #78",
  "set_name": "Pokemon Shining Legends",
  "population": {
    "psa_10": 2628, "psa_9": 6132, "psa_8": 3806,
    "psa_7": 792,  "psa_6": 272,  "psa_5": 162,
    "psa_4": 89,   "psa_3": 63,   "psa_2": 28, "psa_1": 97,
    "total": 14072
  },
  "gem_rate_pct": 18.68,
  "psa_last_updated": "2026-01-04"
}

• Look cards up however you already track them — by our pokeinvest_id, or straight by TCGplayer product id. Both resolve on both endpoints, and both come back on every response so the data joins to whatever you already have.
• IDs that don't move — a pokeinvest_id is never reused and never renumbered. If we ever merge two records the old ID keeps resolving, so nothing you've stored goes stale.
• Honest freshness — populations refresh era by era; every response carries that card's last-updated date so you always know what you're looking at.
• Simple errors — 401 bad key, 404 unknown card, 429 past your monthly cap. Nothing exotic.

Population history: every grade, over time

A dated snapshot of the PSA population report, taken weekly. A point is written only when a card's counts changed, so a flat card has few points and that is the truth, not a gap. Series begin September 2026.

GET https://www.pokeinvest.io/api/population-history/pi_46078
X-API-Key: your_key

{
  "pokeinvest_id": "pi_46078",
  "name": "Mewtwo GX #78",
  "set_name": "Pokemon Shining Legends",
  "grader": "PSA",
  "points": [
    { "date": "2026-09-07", "total": 13990, "psa_10": 2628, "psa_9": 6132, "psa_8": 3806, ... },
    { "date": "2026-10-11", "total": 14102, "psa_10": 2651, "psa_9": 6180, "psa_8": 3831, ... }
  ]
}

Sales: the completed sales behind every price

Date, price, grader and grade, platform, listing. The same rows the card page shows as its receipts; sales held out as the wrong card, a lot, a proxy or damaged are not here. Up to 500 newest; filter with ?grade=PSA+10 or ?days=90.

GET https://www.pokeinvest.io/api/sales/pi_16322?grade=PSA+10
X-API-Key: your_key

{
  "pokeinvest_id": "pi_16322",
  "name": "Gengar EX #108",
  "currency": "USD",
  "count": 4,
  "sales": [
    { "date": "2026-08-30", "price_usd": 27500.0, "grader": "PSA", "grade": "10",
      "platform": "eBay", "sale_type": "marketplace",
      "title": "2004 Pokemon EX Fire Red Leaf Green Gengar ex #108 PSA 10", "url": null },
    { "date": "2026-07-12", "price_usd": 26000.0, "grader": "PSA", "grade": "10",
      "platform": "Goldin", "sale_type": "auction", "url": "https://goldin.co/item/..." }
  ]
}

• Every language — Japanese, Chinese and Korean sets are in the same catalogue with the same IDs; 9,600 Japanese cards carry a measured price today and 17,700 carry a PSA population.
• Auction links are permanent — Goldin, Fanatics, Heritage, MySlabs and Pristine keep lot pages up. eBay retires ended listings and redirects them to a catalogue page, so its link is withheld rather than sent wrong.

Questions