Will Koinly detect duplicate transactions?
Koinly will discard duplicate transactions if imported from the same source and in the same format, for example, if you have a Binance CSV that covers January - April, then get a newer one that includes January - July.
What else can cause duplicate transactions?
Duplicates can also occur if:
Both “trades” and “order” files are imported for the same exchange (as one is single fills from the order book, the other is aggregated)
The files that have different rounding (0.12 and 0.1 are different amounts for Koinly)
The files are in different timezones and the timestamps differ. If you have a file that is in a different timezone, see this article - How to import a CSV file using a different timezone
Note that this duplicate detection does not work if you first imported data using API and are now importing the same data using a CSV file - you will get duplicates here in most cases. This is because different methods of duplicate detection are used by the API / CSV.
If you need to mix CSV and API then simply import CSV files first and setup the API to only import newer transactions. When doing this, you should choose the starting date of the API sync and set it to one day later than your last CSV file (Ex. if you import CSV files for all of 2020 then you should set January 1st, 2021 as the starting date of the API sync).
