# Read centering standards

> Centering thresholds, source status and source URLs for four grading houses.

- **Endpoint**: `GET /v1/centering/standards`
- **Cost**: 1 credits; verified Free trial: 5 measure and 5 confirm calls, independently. Developer excluded.
- **Minimum plan**: growth
- **Cache-Control**: `private, no-store`

Source: https://pokemontcgapi.com/docs/api/centering/standards

No key yet? One call gets you one: `POST /v1/accounts/free` with an `Idempotency-Key` header and your email address returns a working key in the response. Keep the original Idempotency-Key and body for response replay for up to 24 hours, under the conditions in the quickstart. The trial is 800 credits over 30 days once the address is confirmed, no card; paid plans start at 29 € a month. See the [quickstart](https://pokemontcgapi.com/docs/quickstart) and the [pricing](https://pokemontcgapi.com/pricing).

Published or interpreted centering thresholds and source URLs for PSA/BGS/CGC/SGC, including per-band status, reviewed_at, verification provenance and rounding_rule. These dates describe sources, not result certification. Some thresholds are approximate; SGC has no published back table. The sample filters PSA front.

Growth and higher; Developer is excluded. A verified Free trial includes 5 measure and 5 confirm calls, with independent counters. Grade and standards are available during the verified trial without separate call counters. All calls still consume credits. Requires `vision:read`. See the [two-step centering guide](https://pokemontcgapi.com/docs/centering).

Always display: ceiling from centering alone, not a prediction of the final grade. Results are client-confirmed when a person checks the lines; never describe them as verified or certified.

Validation uses `400 INVALID_PARAMETER`: service validation includes `details.service_code` and `details.param`; upload validation may carry only `details.param`. Busy, failed or timed-out processing returns `503 PROVIDER_UNAVAILABLE` with `Retry-After: 2`. A deployment without centering returns `503 FEATURE_NOT_CONFIGURED`. Ineligible plans, unverified Free accounts or exhausted measure/confirm trial counters return `403 PLAN_REQUIRED`; follow `details.next_step` when present. Errors refund credits and trial reservations.

## Query parameters

| Name | Type | Default | Description |
| --- | --- | --- | --- |
| `house` | enum | — | Optional PSA, BGS, CGC or SGC; default all four. |
| `face` | enum | — | Optional front or back; default both. Case and outer whitespace accepted for both filters. |

## Example request

**curl**

```bash
curl -s "https://api.pokemontcgapi.com/v1/centering/standards?house=PSA&face=front" -H "X-Api-Key: $PTCG_API_KEY"
```

**JavaScript**

```js
const res = await fetch("https://api.pokemontcgapi.com/v1/centering/standards?house=PSA&face=front", {
  headers: { "X-Api-Key": process.env.PTCG_API_KEY },
});
if (!res.ok) throw new Error(JSON.stringify(await res.json()));
console.log(await res.json());
```

## Example response

`200 OK` · `Cache-Control: private, no-store`

`response.json`

```json
{
  "data": {
    "normalizations": [],
    "standards": [
      {
        "house": "PSA",
        "face": "front",
        "bands": [
          {
            "value": 10,
            "label": "GEM MT",
            "loose": 55,
            "status": "official",
            "rank": 100
          },
          {
            "value": 9,
            "label": "MINT",
            "loose": 60,
            "status": "official",
            "rank": 90
          },
          {
            "value": 8,
            "label": "NM-MT",
            "loose": 65,
            "status": "official",
            "rank": 80
          },
          {
            "value": 7,
            "label": "NM",
            "loose": 70,
            "status": "official",
            "rank": 70
          },
          {
            "value": 6,
            "label": "EX-MT",
            "loose": 80,
            "status": "official",
            "rank": 60
          },
          {
            "value": 5,
            "label": "EX",
            "loose": 85,
            "status": "official",
            "rank": 50
          },
          {
            "value": 3,
            "label": "VG",
            "loose": 90,
            "status": "official",
            "rank": 30
          },
          {
            "value": 1,
            "label": "PR",
            "loose": 100,
            "status": "official",
            "rank": 10
          }
        ],
        "source": "https://www.psacard.com/gradingstandards",
        "sources": [
          "https://www.psacard.com/gradingstandards"
        ],
        "status": "official",
        "reviewed_at": "2026-10-01",
        "verification": "retrieved",
        "note": "Published percentage thresholds. Only the listed centering bands are used; no missing grades are invented."
      }
    ],
    "rounding_rule": "Normalize to the larger percentage. Round to the nearest whole percentage, halves upward. A threshold t passes only when major < t + 0.5; grade with unrounded values. Distances use published thresholds in percentage points, before rounding.",
    "tag_note": "TAG is excluded because its centering assessment is proprietary and is not represented by these public percentage bands.",
    "summary": "Centering thresholds for PSA (front), including per-band source status and verification provenance. This is a ceiling from centering alone, not a prediction of the final grade.",
    "disclaimer": "This is a ceiling from centering alone, not a prediction of the final grade."
  },
  "meta": {
    "elapsed_ms": 0,
    "engine_version": "1.0.0"
  }
}
```

## Errors

Every error body carries `error.code`, `error.message` and `error.request_id`. Switch on the code, never on the message.

| Status | Code | When |
| --- | --- | --- |
| 401 | `MISSING_API_KEY` | No `X-Api-Key` header and no bearer token on a route that requires one. |
| INSUFFICIENT_SCOPE | INSUFFICIENT_SCOPE | — |
| 403 | `PLAN_REQUIRED` | The feature is outside the plan (movers require Growth; photo recognition has 5 calls after Free email confirmation, then requires Growth), or the account subscription is canceled or suspended. Centering requires Growth or higher; Developer is excluded. After email confirmation the trial includes 5 measure and 5 confirm calls independently; grade and standards use trial credits without separate call counters. Before email confirmation, the message starts with “Confirm your email…”. Follow details.next_step when present. |
| 400 | `INVALID_PARAMETER` | A query parameter has the wrong type or an unsupported value — a non-integer `limit`, an unknown `lang`, an unknown `region`, a sort key that is not sortable. |
| PROVIDER_UNAVAILABLE | PROVIDER_UNAVAILABLE | — |
| 503 | `FEATURE_NOT_CONFIGURED` | The endpoint exists but its optional backend is not configured in this deployment. |
| 429 | `QUOTA_EXCEEDED` | Trial credits, monthly credits or the daily cap are exhausted, and `details` says which: `daily_cap` with `retry_after_s` is the trial daily cap, which resets at midnight UTC; `renews: true` with `resets_at` is the monthly quota of a paid plan; `renews: false` is the trial allowance, which never comes back. `details.next_step` carries the plan, prices and owner action, or email verification when it unlocks the full trial. |
| 403 | `TRIAL_EXPIRED` | The trial has ended: the account is on the trial and its 30 days from signup are over, and this route costs credits. `details.trial_expired_at` is the date, `details.trial_days` the length, and `details.next_step` the owner handoff. Zero-cost routes — `/v1/me`, `/v1/me/usage`, the key routes and `/v1/billing/checkout` — still answer. |

The full taxonomy, with what to do about each code, is on the [errors](https://pokemontcgapi.com/docs/errors) page.