Print the CoinMarketCap USD price history for a particular cryptocurrency in CSV format.
Among other things, this is useful for US tax reporting. If you want to know the cost basis for a trade (or for coins acquired through mining), the IRS requires you to denominate that cost basis in USD. In the case of token-for-token trades (e.g. purchasing ETH with BTC), that requires you know the USD:BTC exchange rate at the time of the trade.
Surprisingly, as of October 2017, it's not easy to get this data in a machine-readable format anywhere online.
Rather than getting the exchange rate at the exact moment of your trade, which is generally not feasible, the IRS standard (at least for similar situations w/stock) is to use the average of a stock's high and low price for the day. CoinMarketCap doesn't provide this figure, but this tool calculates this number and includes it in the output.
Installation:
This script requires Python 2 to be available at /usr/bin/python. This is the case by default with macOS.
Usage:
./coinmarketcap-usd-history.py <currency> <start_year> <end_year>
Where:
<currency>is the (case-insensitive) name of the currency / token as displayed on CoinMarketCap, with dashes in place of spaces<start_year>is the beginning of the range to fetch data for<end_year>is the end of the range to fetch data for
The above information can also be found by running: python coinmarketcap-usd-history.py -h in your terminal.
You can, of course, write results to a file with output redirection:
./coinmarketcap-usd-history.py <currency> <start_year> <end_year> > <output_filename>