It would be really cool if you could check on royaleapi on matches if you and your opponent have faced before and what the result and use of decks were in the matches. I don’t know if this is possible but it would be a really cool feature.
We’ve considered it a few times, but the truth is that unless you are in the top10K or so you are usually facing people you’ve never met; specially considering that our battle logs only cover a few weeks.
So I guess it could be added for top players in the future, but it’s not a feature that can be added for everyone.