API reference

All endpoints are GET, JSON in / JSON out, and require an X-API-Key header.

Authentication

curl -H "X-API-Key: bullion_your_key" \
  https://api.bullionapi.dev/v1/latest

`GET /v1/latest`

Returns current spot prices for all metals in the requested currency.

Param	Required	Description
`currency`	no	ISO 4217 code (default `USD`)

{
  "status": "success",
  "currency": "USD",
  "unit": "toz",
  "metals": { "gold": 4527.86, "silver": 38.42, "platinum": 1523.1, "palladium": 1412.55 },
  "currencies": { "EUR": 0.9134, "GBP": 0.7783, "JPY": 154.22, "CAD": 1.3715 },
  "timestamps": { "metal": "2026-07-08T11:58:50.781Z", "currency": "2026-07-08T11:58:50.781Z" }
}

`GET /v1/timeseries`

Returns daily closes for a date range.

Param	Required	Description
`currency`	yes	ISO 4217 code
`start_date`	yes	`YYYY-MM-DD`
`end_date`	yes	`YYYY-MM-DD` (inclusive)

{
  "status": "success",
  "currency": "USD",
  "unit": "toz",
  "start_date": "2025-07-08",
  "end_date": "2026-07-08",
  "rates": {
    "2026-07-07": { "currencies": {}, "date": "2026-07-07", "metals": { "gold": 4522.66, "silver": 38.38 } },
    "2026-07-08": { "currencies": {}, "date": "2026-07-08", "metals": { "gold": 4527.86, "silver": 38.42 } }
  }
}

Response headers

Header	Description
`x-ratelimit-limit`	Plan monthly limit
`x-ratelimit-remaining`	Requests left this month
`x-ratelimit-reset`	ISO timestamp of next reset

Errors

Status	Code	Meaning
401	`missing_api_key`	No `X-API-Key` header
401	`invalid_api_key`	Key not found or revoked
429	`quota_exceeded`	Monthly plan limit hit