A few years ago I traded cryptocurrency extensively. I eventually ended up with a tax nightmare, needing to account for thousands of trades across several exchanges. After months of talking with my accountant and tax office, I eventually built https://github.com/dleber/capitalg

It was still a lot of work aggregating trade histories from various exchanges into a standardized schema, but I took some comfort in understanding the process. I also avoided the need to share exchange API keys and trading data with 3rd party accounting tools.

If you discover any bugs, please don't tell the tax authorities.