What was a bitcoin worth, in your currency, on a given day or minute, with the provenance to defend the number years later. Read-only, free, no key. Facts, not a tax position.
Endpoints
Price on a day
GET /v1/price?day=2017-12-17&ccy=AUD
Price at a minute
GET /v1/price?day=2021-11-10&time=14:16&ccy=AUD,USD
Coverage
GET /v1/coverage — what ranges and currencies exist
Daily answers return both blockchain.info's cross-exchange average and Bitstamp's close, plus the spread. On 2013-04-10 they differ by 42%; a single number would claim a precision the data does not have.
Intraday
Hourly candles from 2011-08-18, minute candles where backfilled. The answer says which candle it used and never reports a finer precision than it holds.
Non-USD currencies
Crossed through the ECB's daily reference rates on the same fixing day: BTC/CCY = BTC/USD × EUR→CCY ÷ EUR→USD. There is no historical BTC/AUD series; applying today's FX to a 2017 price would be badly wrong.
Weekends
The ECB does not fix on non-business days. The last fixing is carried forward and the answer says which day it used and how far it was carried. A missing BTC day is reported as a hole, never filled.
Refresh
Daily. Every write is an upsert, so history never silently changes under you.
