Hey @1-MG! As long as it doesn't contain live engine eval you can consult opening DBs.
For more info see What counts as cheating on Chess.com? 'Daily Chess - Days per move' section.
Am I allowed to use a tool to see my opponent's opening before daily games?
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Sometimes, before daily games, I use www.openingtree.com to see what my opponent plays in the opening. Is it actually allowed? And, after I know what opening my opponent plays, am I allowed to do some "research" on the opening online? What about if the resources that I use say something like "Nowadays, the move ____ is no longer preferred by modern chess engines...".